Sensor enabled wound therapy dressings and systems implementing cybersecurity

ABSTRACT

In some embodiments, a wound monitoring and/or therapy apparatus includes a wound dressing configured to be positioned in contact with a wound, the wound dressing comprising one or more sensors configured to obtain measurement data of at least one of the wound or periwound. The apparatus can also include a controller configured to maintain a device clock indicative of a non-real time clock, receive measurement data obtained by the one or more sensors, and transmit measurement data to a remote computing device according to a security protocol, the security protocol comprising including the device clock associated with the measurement data in the transmission.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. national stage application ofInternational Patent Application No. PCT/EP2018/0074200, filed Sep. 7,2018, entitled “Sensor Enabled Wound Therapy Dressings And SystemsImplementing Cybersecurity,” which claims priority to U.S. PatentApplication No. 62/556,504, filed on 10 Sep. 2017, entitled “SensorEnabled Wound Therapy Dressings And Systems,” U.S. Patent ApplicationNo. 62/556,505, filed on 11 Sep. 2017, entitled “Sensor Enabled WoundTherapy Dressings And Systems Implementing Cybersecurity,” U.S. PatentApplication No. 62/586,833, filed on 15 Nov. 2017, entitled “SensorEnabled Wound Therapy Dressings And Systems,” and U.K. PatentApplication No. 1718870.7, filed on 15 Nov. 2017, “Sensor Enabled WoundTherapy Dressings And Systems,” each of which is incorporated byreference in its entirety.

BACKGROUND Field

Embodiments of the present disclosure relate to apparatuses, systems,and methods for the treatment of tissues via sensor-enabled monitoringin communication with various therapy regimes.

Description of the Related Art

Nearly all areas of medicine may benefit from improved informationregarding the state of the tissue, organ, or system to be treated,particularly if such information is gathered in real-time duringtreatment. Many types of treatments are still routinely performedwithout the use of sensor data collection; instead, such treatments relyupon visual inspection by a caregiver or other limited means rather thanquantitative sensor data. For example, in the case of wound treatmentvia dressings and/or negative pressure wound therapy, data collection isgenerally limited to visual inspection by a caregiver and often theunderlying wounded tissue may be obscured by bandages or other visualimpediments. Even intact, unwounded skin may have underlying damage thatis not visible to the naked eye, such as a compromised vascular ordeeper tissue damage that may lead to an ulcer. Similar to woundtreatment, during orthopedic treatments requiring the immobilization ofa limb with a cast or other encasement, only limited information isgathered on the underlying tissue. In instances of internal tissuerepair, such as a bone plate, continued direct sensor-driven datacollection is not performed. Further, braces and/or sleeves used tosupport musculoskeletal function do not monitor the functions of theunderlying muscles or the movement of the limbs. Outside of directtreatments, common hospital room items such as beds and blankets couldbe improved by adding capability to monitor patient parameters.

Therefore, there is a need for improved sensor monitoring, particularlythrough the use of sensor-enabled substrates which can be incorporatedinto existing treatment regimes.

SUMMARY

In some embodiments, a wound monitoring and/or therapy apparatusincludes a wound dressing configured to be positioned in contact with awound, the wound dressing including one or more sensors configured toobtain measurement data of at least one of the wound or periwound and acontroller configured to maintain a device clock indicative of anon-real time clock, receive measurement data obtained by the one ormore sensors, and transmit measurement data to a remote computing deviceaccording to a security protocol, the security protocol comprisingincluding the device clock associated with the measurement data in thetransmission.

The apparatus of the preceding paragraph can include one or more of thefollowing features. The wound dressing can include a substantiallyflexible wound contact layer supporting the one or more sensors. Thesecurity protocol can further include encrypting the measurement data.The security protocol can further include not including in thetransmission patient identification information or real time clockinformation associated with the measurement data. Transmission of themeasurement data with the associated device clock data can causes theremote computing device to utilize the device clock data to correlatethe measurement data with real time clock data. The controller can befurther configured to transmit initial device clock data to the remotecomputing device during initialization, and transmission of themeasurement data with the associated device clock data can cause theremote computing device to determine elapsed time relative to theinitial transmission based on comparison of the initial device clockdata and device clock data associated with the measurement data. Thecontroller can be configured to maintain the device clock when power issupplied to the controller. The controller can be configured to maintainthe device clock by counting up from zero, a random number, or a uniquenumber. In response to a power interruption, the controller can befurther configured to reestablish the device clock from a previousdevice clock value before the power interruption.

In some embodiments, a wound monitoring and/or therapy system includesthe apparatus of any of the preceding paragraphs, a communication deviceconfigured to be connected to the controller of the apparatus andfurther configured to periodically receive data from the controller, anda computing device configured to be connected to the communicationdevice, the computing device further configured to receive data from thecommunication device, the computing device further configured to beconnected to another remote computing device configured to receive andaggregate data from the computing device.

The system of the preceding paragraph can include one or more of thefollowing features. The system can further include another computingdevice configured to obtain one or more images of at least one of thewound or periwound. The computing device can be configured tocommunicate the one or more images to the another remote computingdevice. The wound dressing can further include an antenna configured tocommunicate the measurement data to at least one of the controller orcommunication device. The system can further include a skin perfusionmeasurement device configured to measure skin perfusion pressure in atarget area of the patient, wherein the computing device is can befurther configured to be connected to the perfusion measurement deviceand receive data from the perfusion measurement device. Thecommunication device can be configured to be connected to the controllerusing near field communication (NFC) protocol.

In some embodiments, a method of operating a wound dressing configuredto be positioned in contact with a wound, the wound dressing includingone or more sensors configured to obtain measurement data of at leastone of the wound or periwound, the method includes, by a controllerconfigured to be connected to or supported by the wound dressing,maintaining a device clock indicative of a non-real time clock,receiving measurement data obtained by the one or more sensors, andtransmitting measurement data to a remote computing device according toa security protocol by including the device clock associated with themeasurement data in the transmission.

The method of the preceding paragraph can include one or more of thefollowing features. The security protocol can further include encryptingthe measurement data. The security protocol can further comprise notincluding in the transmission patient identification information or realtime clock information associated with the measurement data.Transmission of the measurement data with the associated device clockdata can cause the remote computing device to utilize the device clockdata to correlate the measurement data with real time clock data. Themethod can include, by the controller, transmitting initial device clockdata to the remote computing device during initialization, whereintransmission of the measurement data with the associated device clockdata can cause the remote computing device to determine elapsed timerelative to the initial transmission based on comparison of the initialdevice clock data and device clock data associated with the measurementdata. The method can further include maintaining the device clock whenpower is supplied to the controller. Maintaining the device clock can beperformed by counting up from zero, a random number, or a unique number.In response to a power interruption, the method can includereestablishing the device clock from a previous device clock valuebefore the power interruption

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described hereinafter,by way of example only, with reference to the accompanying drawings inwhich:

FIG. 1A illustrates a wound monitoring and therapy system according tosome embodiments;

FIG. 1B illustrate the use of a wound monitoring and therapy systemaccording to some embodiments;

FIGS. 1C-1H illustrate sensor enabled wound dressings according to someembodiments;

FIG. 2A illustrates a negative pressure wound treatment system accordingto some embodiments;

FIG. 2B illustrates a wound dressing according to some embodiments;

FIG. 3 illustrates a sensor array illustrating the sensor placementincorporated into a wound dressing according to some embodiments;

FIG. 4A illustrates a flexible sensor array including a sensor arrayportion, a tail portion and a connector pad end portion according tosome embodiments;

FIG. 4B illustrates flexible circuit boards with different sensor arraygeometries according to some embodiments;

FIG. 4C illustrates the sensor array portion 301B of a sensor arrayshown in FIG. 4B;

FIG. 4D illustrates a flexible sensor array incorporated into aperforated wound contact layer according to some embodiments;

FIG. 4E illustrates a control module according to some embodiments;

FIGS. 5A-5B illustrate a wound dressing with a plurality of electroniccomponents according to some embodiments; and

FIG. 6 illustrates skin perfusion pressure determination according tosome embodiments.

DETAILED DESCRIPTION

Embodiments disclosed herein relate to apparatuses and methods ofmonitoring and treating biological tissue with sensor-enabledsubstrates. The embodiments disclosed herein are not limited totreatment or monitoring of a particular type of tissue or injury,instead the sensor-enabled technologies disclosed herein are broadlyapplicable to any type of therapy that may benefit from sensor-enabledsubstrates. Some implementations utilize sensors and data collectionrelied upon by health care providers to make both diagnostic and patientmanagement decisions.

Some embodiments disclosed herein relate to the use of sensors mountedon or embedded within substrates configured to be used in the treatmentof both intact and damaged human or animal tissue. Such sensors maycollect information about the surrounding tissue and transmit suchinformation to a computing device or a caregiver to be utilized infurther treatment. In certain embodiments, such sensors may be attachedto the skin anywhere on the body, including areas for monitoringarthritis, temperature, or other areas that may be prone to problems andrequire monitoring. Sensors disclosed herein may also incorporatemarkers, such as radiopaque markers, to indicate the presence of thedevice, for example prior to performing an MRI or other technique.

The sensor embodiments disclosed herein may be used in combination withclothing. Non-limiting examples of clothing for use with embodiments ofthe sensors disclosed herein include shirts, pants, trousers, dresses,undergarments, outer-garments, gloves, shoes, hats, and other suitablegarments. In certain embodiments, the sensor embodiments disclosedherein may be welded into or laminated into/onto the particulargarments. The sensor embodiments may be printed directly onto thegarment and/or embedded into the fabric. Breathable and printablematerials such as microporous membranes may also be suitable.

Sensor embodiments disclosed herein may be incorporated into cushioningor bed padding, such as within a hospital bed, to monitor patientcharacteristics, such as any characteristic disclosed herein. In certainembodiments, a disposable film containing such sensors could be placedover the hospital bedding and removed/replaced as needed.

In some implementations, the sensor embodiments disclosed herein mayincorporate energy harvesting, such that the sensor embodiments areself-sustaining. For example, energy may be harvested from thermalenergy sources, kinetic energy sources, chemical gradients, or anysuitable energy source.

The sensor embodiments disclosed herein may be utilized inrehabilitation devices and treatments, including sports medicine. Forexample, the sensor embodiments disclosed herein may be used in braces,sleeves, wraps, supports, and other suitable items. Similarly, thesensor embodiments disclosed herein may be incorporated into sportingequipment, such as helmets, sleeves, and/or pads. For example, suchsensor embodiments may be incorporated into a protective helmet tomonitor characteristics such as acceleration, which may be useful inconcussion diagnosis.

The sensor embodiments disclosed herein may be used in coordination withsurgical devices, for example, the NAVIO surgical system by Smith &Nephew Inc. In implementations, the sensor embodiments disclosed hereinmay be in communication with such surgical devices to guide placement ofthe surgical devices. In some implementations, the sensor embodimentsdisclosed herein may monitor blood flow to or away from the potentialsurgical site or ensure that there is no blood flow to a surgical site.Further surgical data may be collected to aid in the prevention ofscarring and monitor areas away from the impacted area.

To further aid in surgical techniques, the sensors disclosed herein maybe incorporated into a surgical drape to provide information regardingtissue under the drape that may not be immediately visible to the nakedeye. For example, a sensor embedded flexible drape may have sensorspositioned advantageously to provide improved area-focused datacollection. In certain implementations, the sensor embodiments disclosedherein may be incorporated into the border or interior of a drape tocreate fencing to limit/control the surgical theater.

Sensor embodiments as disclosed herein may also be utilized forpre-surgical assessment. For example, such sensor embodiments may beused to collect information about a potential surgical site, such as bymonitoring skin and the underlying tissues for a possible incision site.For example, perfusion levels or other suitable characteristics may bemonitored at the surface of the skin and deeper in the tissue to assesswhether an individual patient may be at risk for surgical complications.Sensor embodiments such as those disclosed herein may be used toevaluate the presence of microbial infection and provide an indicationfor the use of antimicrobials. Further, sensor embodiments disclosedherein may collect further information in deeper tissue, such asidentifying pressure ulcer damage and/or the fatty tissue levels.

The sensor embodiments disclosed herein may be utilized incardiovascular monitoring. For example, such sensor embodiments may beincorporated into a flexible cardiovascular monitor that may be placedagainst the skin to monitor characteristics of the cardiovascular systemand communicate such information to another device and/or a caregiver.For example, such a device may monitor pulse rate, oxygenation of theblood, and/or electrical activity of the heart. Similarly, the sensorembodiments disclosed herein may be utilized for neurophysiologicalapplications, such as monitoring electrical activity of neurons.

The sensor embodiments disclosed herein may be incorporated intoimplantable devices, such as implantable orthopedic implants, includingflexible implants. Such sensor embodiments may be configured to collectinformation regarding the implant site and transmit this information toan external source. In some embodiments, an internal source may alsoprovide power for such an implant.

The sensor embodiments disclosed herein may also be utilized formonitoring biochemical activity on the surface of the skin or below thesurface of the skin, such as lactose buildup in muscle or sweatproduction on the surface of the skin. In some embodiments, othercharacteristics may be monitored, such as glucose concentration, urineconcentration, tissue pressure, skin temperature, skin surfaceconductivity, skin surface resistivity, skin hydration, skin maceration,and/or skin ripping.

Sensor embodiments as disclosed herein may be incorporated into Ear,Nose, and Throat (ENT) applications. For example, such sensorembodiments may be utilized to monitor recovery from ENT-relatedsurgery, such as wound monitoring within the sinus passage.

As described in greater detail below, the sensor embodiments disclosedherein may encompass sensor printing technology with encapsulation, suchas encapsulation with a polymer film. Such a film may be constructedusing any polymer described herein, such as polyurethane. Encapsulationof the sensor embodiments may provide waterproofing of the electronicsand protection from local tissue, local fluids, and other sources ofpotential damage.

In certain embodiments, the sensors disclosed herein may be incorporatedinto an organ protection layer such as disclosed below. Such asensor-embedded organ protection layer may both protect the organ ofinterest and confirm that the organ protection layer is in position andproviding protection. Further, a sensor-embedded organ protection layermay be utilized to monitor the underlying organ, such as by monitoringblood flow, oxygenation, and other suitable markers of organ health. Insome embodiments, a sensor-enabled organ protection layer may be used tomonitor a transplanted organ, such as by monitoring the fat and musclecontent of the organ. Further, sensor-enabled organ protection layersmay be used to monitor an organ during and after transplant, such asduring rehabilitation of the organ.

The sensor embodiments disclosed herein may be incorporated intotreatments for wounds (disclosed in greater detail below) or in avariety of other applications. Non-limiting examples of additionalapplications for the sensor embodiments disclosed herein include:monitoring and treatment of intact skin, cardiovascular applicationssuch as monitoring blood flow, orthopedic applications such asmonitoring limb movement and bone repair, neurophysiologicalapplications such as monitoring electrical impulses, and any othertissue, organ, system, or condition that may benefit from improvedsensor-enabled monitoring.

Wound Therapy

Some embodiments disclosed herein relate to wound therapy for a human oranimal body. Therefore, any reference to a wound herein can refer to awound on a human or animal body, and any reference to a body herein canrefer to a human or animal body. The disclosed technology embodimentsmay relate to preventing or minimizing damage to physiological tissue orliving tissue, or to the treatment of damaged tissue (for example, awound as described herein) wound with or without reduced pressure,including for example a source of negative pressure and wound dressingcomponents and apparatuses. The apparatuses and components comprisingthe wound overlay and packing materials or internal layers, if any, aresometimes collectively referred to herein as dressings. In someembodiments, the wound dressing can be provided to be utilized withoutreduced pressure.

Some embodiments disclosed herein relate to wound therapy for a human oranimal body. Therefore, any reference to a wound herein can refer to awound on a human or animal body, and any reference to a body herein canrefer to a human or animal body. The disclosed technology embodimentsmay relate to preventing or minimizing damage to physiological tissue orliving tissue, or to the treatment of damaged tissue (for example, awound as described herein).

As used herein the expression “wound” may include an injury to livingtissue may be caused by a cut, blow, or other impact, typically one inwhich the skin is cut or broken. A wound may be a chronic or acuteinjury. Acute wounds occur as a result of surgery or trauma. They movethrough the stages of healing within a predicted timeframe. Chronicwounds typically begin as acute wounds. The acute wound can become achronic wound when it does not follow the healing stages resulting in alengthened recovery. It is believed that the transition from acute tochronic wound can be due to a patient being immuno-compromised.

Chronic wounds may include for example: venous ulcers (such as thosethat occur in the legs), which account for the majority of chronicwounds and mostly affect the elderly, diabetic ulcers (for example, footor ankle ulcers), peripheral arterial disease, pressure ulcers, orepidermolysis bullosa (EB).

Examples of other wounds include, but are not limited to, abdominalwounds or other large or incisional wounds, either as a result ofsurgery, trauma, sterniotomies, fasciotomies, or other conditions,dehisced wounds, acute wounds, chronic wounds, subacute and dehiscedwounds, traumatic wounds, flaps and skin grafts, lacerations, abrasions,contusions, burns, diabetic ulcers, pressure ulcers, stoma, surgicalwounds, trauma and venous ulcers or the like.

Wounds may also include a deep tissue injury. Deep tissue injury is aterm proposed by the National Pressure Ulcer Advisory Panel (NPUAP) todescribe a unique form of pressure ulcers. These ulcers have beendescribed by clinicians for many years with terms such as purplepressure ulcers, ulcers that are likely to deteriorate and bruises onbony prominences.

Wound may also include tissue at risk of becoming a wound as discussedherein. For example, tissue at risk may include tissue over a bonyprotuberance (at risk of deep tissue injury/insult) or pre-surgicaltissue (for example, knee tissue) that may has the potential to be cut(for example, for joint replacement/surgical alteration/reconstruction).

Some embodiments relate to methods of treating a wound with thetechnology disclosed herein in conjunction with one or more of thefollowing: advanced footwear, turning a patient, offloading (such as,offloading diabetic foot ulcers), treatment of infection, systemix,antimicrobial, antibiotics, surgery, removal of tissue, affecting bloodflow, physiotherapy, exercise, bathing, nutrition, hydration, nervestimulation, ultrasound, electrostimulation, oxygen therapy, microwavetherapy, active agents ozone, antibiotics, antimicrobials, or the like.

Alternatively or additionally, a wound may be treated using topicalnegative pressure and/or traditional advanced wound care, which is notaided by the using of applied negative pressure (may also be referred toas non-negative pressure therapy).

Advanced wound care may include use of an absorbent dressing, anocclusive dressing, use of an antimicrobial and/or debriding agents in awound dressing or adjunct, a pad (for example, a cushioning orcompressive therapy, such as stockings or bandages), or the like.

In some embodiments, treatment of such wounds can be performed usingtraditional wound care, wherein a dressing can be applied to the woundto facilitate and promote healing of the wound.

Some embodiments relate to methods of manufacturing a wound dressingcomprising providing a wound dressing as disclosed herein.

The wound dressings that may be utilized in conjunction with thedisclosed technology include any known dressing in the art. Thetechnology is applicable to negative pressure therapy treatment as wellas non-negative pressure therapy treatment.

In some embodiments, a wound dressing comprises one or more absorbentlayer(s). The absorbent layer may be a foam or a superabsorbent.

In some embodiments, wound dressings may comprise a dressing layerincluding a polysaccharide or modified polysaccharide, apolyvinylpyrrolidone, a polyvinyl alcohol, a polyvinyl ether, apolyurethane, a polyacrylate, a polyacrylamide, collagen, or gelatin ormixtures thereof. Dressing layers comprising the polymers listed areknown in the art as being useful for forming a wound dressing layer foreither negative pressure therapy or non-negative pressure therapy.

In some embodiments, the polymer matrix may be a polysaccharide ormodified polysaccharide.

In some embodiments, the polymer matrix may be a cellulose. Cellulosematerial may include hydrophilically modified cellulose such as methylcellulose, carboxymethyl cellulose (CMC), carboxymethyl cellulose (CEC),ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxypropylcellulose, hydroxypropylmethyl cellulose, carboxyethyl sulphonatecellulose, cellulose alkyl sulphonate, or mixtures thereof.

In certain embodiments, cellulose material may be cellulose alkylsulphonate. The alkyl moiety of the alkyl sulphonate substituent groupmay have an alkyl group having 1 to 6 carbon atoms, such as methyl,ethyl, propyl, or butyl. The alkyl moiety may be branched or unbranched,and hence suitable propyl sulphonate substituents may be 1- or2-methyl-ethylsulphonate. Butyl sulphonate substituents may be2-ethyl-ethylsulphonate, 2,2-dimethyl-ethylsulphonate, or1,2-dimethyl-ethylsulphonate. The alkyl sulphonate substituent group maybe ethyl sulphonate. The cellulose alkyl sulphonate is described inWO10061225, US2016/114074, US2006/0142560, or U.S. Pat. No. 5,703,225,the disclosures of which are hereby incorporated by reference in theirentirety.

Cellulose alkyl sulfonates may have varying degrees of substitution, thechain length of the cellulose backbone structure, and the structure ofthe alkyl sulfonate substituent. Solubility and absorbency are largelydependent on the degree of substitution: as the degree of substitutionis increased, the cellulose alkyl sulfonate becomes increasinglysoluble. It follows that, as solubility increases, absorbency increases.

In some embodiments, a wound dressing also comprises a top or coverlayer.

The thickness of the wound dressing disclosed herein may be between 1 to20, or 2 to 10, or 3 to 7 mm.

In some embodiments, the disclosed technology may be used in conjunctionwith a non-negative pressure dressing. A non-negative pressure wounddressing suitable for providing protection at a wound site may comprise:

an absorbent layer for absorbing wound exudate and

an obscuring element for at least partially obscuring a view of woundexudate absorbed by the absorbent layer in use.

The obscuring element may be partially translucent.

The obscuring element may be a masking layer.

The non-negative pressure wound dressing may further comprise a regionin or adjacent the obscuring element for allowing viewing of theabsorbent layer. For example, the obscuring element layer may beprovided over a central region of the absorbent layer and not over aborder region of the absorbent layer. In some embodiments, the obscuringelement is of hydrophilic material or is coated with a hydrophilicmaterial.

The obscuring element may comprise a three-dimensional knitted spacerfabric. The spacer fabric is known in the art and may include a knittedspacer fabric layer.

The obscuring element may further comprise an indicator for indicatingthe need to change the dressing.

In some embodiments, the obscuring element is provided as a layer atleast partially over the absorbent layer, further from a wound site thanthe absorbent layer in use.

The non-negative pressure wound dressing may further comprise aplurality of openings in the obscuring element for allowing fluid tomove therethrough. The obscuring element may comprise, or may be coatedwith, a material having size-exclusion properties for selectivelypermitting or preventing passage of molecules of a predetermined size orweight.

The obscuring element may be configured to at least partially mask lightradiation having wavelength of 600 nm and less.

The obscuring element may be configured to reduce light absorption by50% or more.

The obscuring element may be configured to yield a CIE L* value of 50 ormore, and optionally 70 or more. In some embodiments, the obscuringelement may be configured to yield a CIE L* value of 70 or more.

In some embodiments, the non-negative pressure wound dressing mayfurther comprise at least one of a wound contact layer, a foam layer, anodor control element, a pressure-resistant layer and a cover layer.

In some embodiments, the cover layer is present, and the cover layer isa translucent film. Typically, the translucent film has a moisturevapour permeability of 500 g/m2/24 hours or more.

The translucent film may be a bacterial barrier.

In some embodiments, the non-negative pressure wound dressing asdisclosed herein comprises the wound contact layer and the absorbentlayer overlies the wound contact layer. The wound contact layer carriesan adhesive portion for forming a substantially fluid tight seal overthe wound site.

The non-negative pressure wound dressing as disclosed herein maycomprise the obscuring element and the absorbent layer being provided asa single layer.

In some embodiments, the non-negative pressure wound dressing disclosedherein comprises the foam layer, and the obscuring element is of amaterial comprising components that may be displaced or broken bymovement of the obscuring element.

In some embodiments, the non-negative pressure wound dressing comprisesan odor control element, and in another embodiment the dressing does notinclude an odor control element. When present, the odor control elementmay be dispersed within or adjacent the absorbent layer or the obscuringelement. Alternatively, when present the odor control element may beprovided as a layer sandwiched between the foam layer and the absorbentlayer.

In some embodiments, the disclosed technology for a non-negativepressure wound dressing comprises a method of manufacturing a wounddressing, comprising: providing an absorbent layer for absorbing woundexudate; and providing an obscuring element for at least partiallyobscuring a view of wound exudate absorbed by the absorbent layer inuse.

In some embodiments, the non-negative pressure wound dressing is may besuitable for providing protection at a wound site, comprising: anabsorbent layer for absorbing wound exudate; and a shielding layerprovided over the absorbent layer, and further from a wound-facing sideof the wound dressing than the absorbent layer. The shielding layer maybe provided directly over the absorbent layer. In some embodiments, theshielding layer comprises a three-dimensional spacer fabric layer.

The shielding layer increases the area over which a pressure applied tothe dressing is transferred by 25% or more or the initial area ofapplication. For example the shielding layer increases the area overwhich a pressure applied to the dressing is transferred by 50% or more,and optionally by 100% or more, and optionally by 200% or more.

The shielding layer may comprise 2 or more sub-layers, wherein a firstsub-layer comprises through holes and a further sub-layer comprisesthrough holes and the through holes of the first sub-layer are offsetfrom the through holes of the further sub-layer.

The non-negative pressure wound dressing as disclosed herein may furthercomprise a permeable cover layer for allowing the transmission of gasand vapour therethrough, the cover layer provided over the shieldinglayer, wherein through holes of the cover layer are offset from throughholes of the shielding layer.

The non-negative pressure wound dressing may be suitable for treatmentof pressure ulcers.

A more detailed description of the non-negative pressure dressingdisclosed hereinabove is provided in WO2013007973, the entirety of whichis hereby incorporated by reference.

In some embodiments, the non-negative pressure wound dressing may be amulti-layered wound dressing comprising: a fibrous absorbent layer forabsorbing exudate from a wound site; and a support layer configured toreduce shrinkage of at least a portion of the wound dressing.

In some embodiments, the multi-layered wound dressing disclosed herein,further comprises a liquid impermeable film layer, wherein the supportlayer is located between the absorbent layer and the film layer.

The support layer disclosed herein may comprise a net. The net maycomprise a geometric structure having a plurality of substantiallygeometric apertures extending therethrough. The geometric structure mayfor example comprise a plurality of bosses substantially evenly spacedand joined by polymer strands to form the substantially geometricapertures between the polymer strands.

The net may be formed from high density polyethylene.

The apertures may have an area from 0.005 to 0.32 mm2.

The support layer may have a tensile strength from 0.05 to 0.06 Nm.

The support layer may have a thickness of from 50 to 150 μm.

In some embodiments, the support layer is located directly adjacent theabsorbent layer. Typically, the support layer is bonded to fibers in atop surface of the absorbent layer. The support layer may furthercomprise a bonding layer, wherein the support layer is heat laminated tothe fibers in the absorbent layer via the bonding layer. The bondinglayer may comprise a low melting point adhesive such as ethylene-vinylacetate adhesive.

In some embodiments, the multi-layered wound dressing disclosed hereinfurther comprises an adhesive layer attaching the film layer to thesupport layer.

In some embodiments, the multi-layered wound dressing disclosed hereinfurther comprises a wound contact layer located adjacent the absorbentlayer for positioning adjacent a wound. The multi-layered wound dressingmay further comprise a fluid transport layer between the wound contactlayer and the absorbent layer for transporting exudate away from a woundinto the absorbent layer.

A more detailed description of the multi-layered wound dressingdisclosed hereinabove is provided in GB patent application filed on 28Oct. 2016 with application number GB1618298.2, the entirety of which ishereby incorporated by reference.

In some embodiments, the disclosed technology may be incorporated in awound dressing comprising a vertically lapped material comprising: afirst layer of an absorbing layer of material, and a second layer ofmaterial, wherein the first layer being constructed from at least onelayer of non-woven textile fibers, the non-woven textile fibers beingfolded into a plurality of folds to form a pleated structure. In someembodiments, the wound dressing further comprises a second layer ofmaterial that is temporarily or permanently connected to the first layerof material.

Typically the vertically lapped material has been slitted.

In some embodiments, the first layer has a pleated structure having adepth determined by the depth of pleats or by the slitting width. Thefirst layer of material may be a moldable, lightweight, fiber-basedmaterial, blend of material or composition layer.

The first layer of material may comprise one or more of manufacturedfibers from synthetic, natural or inorganic polymers, natural fibers ofa cellulosic, proteinaceous or mineral source.

The wound dressing may comprise two or more layers of the absorbinglayer of material vertically lapped material stacked one on top of theother, wherein the two or more layers have the same or differentdensities or composition.

The wound dressing may in some embodiments comprise only one layer ofthe absorbing layer of material vertically lapped material.

The absorbing layer of material is a blend of natural or synthetic,organic or inorganic fibers, and binder fibers, or bicomponent fiberstypically PET with a low melt temperature PET coating to soften atspecified temperatures and to act as a bonding agent in the overallblend.

In some embodiments, the absorbing layer of material may be a blend of 5to 95% thermoplastic polymer, and 5 to 95 wt % of a cellulose orderivative thereof.

In some embodiments, the wound dressing disclosed herein has a secondlayer comprises a foam or a dressing fixative.

The foam may be a polyurethane foam. The polyurethane foam may have anopen or closed pore structure.

The dressing fixative may include bandages, tape, gauze, or backinglayer.

In some embodiments, the wound dressing as disclosed herein comprisesthe absorbing layer of material connected directly to a second layer bylamination or by an adhesive, and the second layer is connected to adressing fixative layer. The adhesive may be an acrylic adhesive, or asilicone adhesive.

In some embodiments, the wound dressing as disclosed herein furthercomprises layer of a superabsorbent fiber, or a viscose fiber or apolyester fiber.

In some embodiments, the wound dressing as disclosed herein furthercomprises a backing layer. The backing layer may be a transparent oropaque film. Typically the backing layer comprises a polyurethane film(typically a transparent polyurethane film).

A more detailed description of the multi-layered wound dressingdisclosed hereinabove is provided in GB patent applications filed on 12Dec. 2016 with application number GB1621057.7; and 22 Jun. 2017 withapplication number GB1709987.0, the entirety of each of which is herebyincorporated by reference.

In some embodiments, the non-negative pressure wound dressing maycomprise an absorbent component for a wound dressing, the componentcomprising a wound contacting layer comprising gel forming fibers boundto a foam layer, wherein the foam layer is bound directly to the woundcontact layer by an adhesive, polymer based melt layer, by flamelamination or by ultrasound.

The absorbent component may be in a sheet form.

The wound contacting layer may comprise a layer of woven or non-woven orknitted gel forming fibers.

The foam layer may be an open cell foam, or closed cell foam, typicallyan open cell foam. The foam layer is a hydrophilic foam.

The wound dressing may comprise the component that forms an island indirect contact with the wound surrounded by periphery of adhesive thatadheres the dressing to the wound. The adhesive may be a silicone oracrylic adhesive, typically a silicone adhesive.

The wound dressing may be covered by a film layer on the surface of thedressing furthest from the wound.

A more detailed description of the wound dressing of this typehereinabove is provided in EP2498829, the entirety of which is herebyincorporated by reference.

In some embodiments, the non-negative pressure wound dressing maycomprise a multi layered wound dressing for use on wounds producing highlevels of exudate, characterized in that the dressing comprising: atransmission layer having an MVTR of at least 300 gm2/24 hours, anabsorbent core comprising gel forming fibers capable of absorbing andretaining exudate, a wound contacting layer comprising gel formingfibers which transmits exudate to the absorbent core and a keying layerpositioned on the absorbent core, the absorbent core and woundcontacting layer limiting the lateral spread of exudate in the dressingto the region of the wound.

The wound dressing may be capable of handling at least 6 g (or 8 g and15 g) of fluid per 10 cm2 of dressing in 24 hours.

The wound dressing may comprise gel forming fibers that are chemicallymodified cellulosic fibers in the form of a fabric. The fibers mayinclude carboxymethylated cellulose fibers, typically sodiumcarboxymethylcellulose fiber.

The wound dressing may comprise a wound contact layer with a lateralwicking rate from 5 mm per minute to 40 mm per minute. The wound contactlayer may have a fiber density between 25 gm2 and 55 gm2, such as 35gm2.

The absorbent core may have an absorbency of exudate of at least 10 g/g,and typically a rate of lateral wicking of less the 20 mm per minute.

The absorbent core may have a blend in the range of up to 25% cellulosicfibers by weight and 75% to 100% gel forming fibers by weight.

Alternatively, the absorbent core may have a blend in the range of up to50% cellulosic fibers by weight and 50% to 100% gel forming fibers byweight. For example the blend is in the range of 50% cellulosic fibersby weight and 50% gel forming fibers by weight.

The fiber density in the absorbent core may be between 150 gm2 and 250gm2, or about 200 gm2.

The wound dressing when wet may have shrinkage that is less than 25% orless than 15% of its original size/dimension.

The wound dressing may comprise a transmission layer and the layer is afoam. The transmission layer may be a polyurethane foam laminated to apolyurethane film.

The wound dressing may comprise one or more layers selected from thegroup comprising a soluble medicated film layer; an odor-absorbinglayer; a spreading layer and an additional adhesive layer.

The wound dressing may be 2 mm and 4 mm thick.

The wound dressing may be characterized in that the keying layer bondsthe absorbent core to a neighboring layer. In some embodiments, thekeying layer may be positioned on either the wound facing side of theabsorbent core or the non-wound facing side of the absorbent core. Insome embodiments, the keying layer is positioned between the absorbentcore and the wound contact layer. The keying layer is a polyamide web.

A more detailed description of the wound dressing of this typehereinabove is provided in EP1718257, the entirety of which is herebyincorporated by reference.

In some embodiments, the non-negative pressure wound dressing may be acompression bandage. Compression bandages are known for use in thetreatment of oedema and other venous and lymphatic disorders, e.g., ofthe lower limbs.

A compression bandage systems typically employ multiple layers includinga padding layer between the skin and the compression layer or layers.The compression bandage may be useful for wounds such as handling venousleg ulcers.

The compression bandage in some embodiments may comprise a bandagesystem comprising an inner skin facing layer and an elastic outer layer,the inner layer comprising a first ply of foam and a second ply of anabsorbent nonwoven web, the inner layer and outer layer beingsufficiently elongated so as to be capable of being wound about apatient's limb. A compression bandage of this type is disclosed inWO99/58090, the entirety of which is hereby incorporated by reference.

In some embodiments, the compression bandage system comprises: a) aninner skin facing, elongated, elastic bandage comprising: (i) anelongated, elastic substrate, and

(ii) an elongated layer of foam, said foam layer being affixed to a faceof said substrate and extending 33% or more across said face ofsubstrate in transverse direction and 67% or more across said face ofsubstrate in longitudinal direction; and b) an outer, elongated,self-adhering elastic bandage; said bandage having a compressive forcewhen extended; wherein, in use, said foam layer of the inner bandagefaces the skin and the outer bandage overlies the inner bandage. Acompression bandage of this type is disclosed in WO2006/110527, theentirety of which is hereby incorporated by reference.

In some embodiments other compression bandage systems such as thosedisclosed in U.S. Pat. No. 6,759,566 and US 2002/0099318, the entiretyof each of which is hereby incorporated by reference.

Negative Pressure Wound Dressing

In some embodiments, treatment of such wounds can be performed usingnegative pressure wound therapy, wherein a reduced or negative pressurecan be applied to the wound to facilitate and promote healing of thewound. It will also be appreciated that the wound dressing and methodsas disclosed herein may be applied to other parts of the body, and arenot necessarily limited to treatment of wounds.

It will be understood that embodiments of the present disclosure aregenerally applicable to use in topical negative pressure (“TNP”) therapysystems. Briefly, negative pressure wound therapy assists in the closureand healing of many forms of “hard to heal” wounds by reducing tissueoedema; encouraging blood flow and granular tissue formation; removingexcess exudate and may reduce bacterial load (and thus infection risk).In addition, the therapy allows for less disturbance of a wound leadingto more rapid healing. TNP therapy systems may also assist on thehealing of surgically closed wounds by removing fluid and by helping tostabilize the tissue in the apposed position of closure. A furtherbeneficial use of TNP therapy can be found in grafts and flaps whereremoval of excess fluid is important and close proximity of the graft totissue is required in order to ensure tissue viability.

Negative pressure therapy can be used for the treatment of open orchronic wounds that are too large to spontaneously close or otherwisefail to heal by means of applying negative pressure to the site of thewound. Topical negative pressure (TNP) therapy or negative pressurewound therapy (NPWT) involves placing a cover that is impermeable orsemi-permeable to fluids over the wound, using various means to seal thecover to the tissue of the patient surrounding the wound, and connectinga source of negative pressure (such as a vacuum pump) to the cover in amanner so that negative pressure is created and maintained under thecover. It is believed that such negative pressures promote wound healingby facilitating the formation of granulation tissue at the wound siteand assisting the body's normal inflammatory process whilesimultaneously removing excess fluid, which may contain adversecytokines or bacteria.

Some of the dressings used in NPWT can include many different types ofmaterials and layers, for example, gauze, pads, foam pads or multi-layerwound dressings. One example of a multi-layer wound dressing is the PICOdressing, available from Smith & Nephew, includes a wound contact layerand a superabsorbent layer beneath a backing layer to provide acanister-less system for treating a wound with NPWT. The wound dressingmay be sealed to a suction port providing connection to a length oftubing, which may be used to pump fluid out of the dressing or totransmit negative pressure from a pump to the wound dressing.Additionally, RENASYS-F, RENASYS-G, RENASYS-AB, and RENASYS-F/AB,available from Smith & Nephew, are additional examples of NPWT wounddressings and systems. Another example of a multi-layer wound dressingis the ALLEVYN Life dressing, available from Smith & Nephew, whichincludes a moist wound environment dressing that is used to treat thewound without the use of negative pressure.

As is used herein, reduced or negative pressure levels, such as −X mmHg,represent pressure levels relative to normal ambient atmosphericpressure, which can correspond to 760 mmHg (or 1 atm, 29.93 inHg,101.325 kPa, 14.696 psi, etc.). Accordingly, a negative pressure valueof −X mmHg reflects absolute pressure that is X mmHg below 760 mmHg or,in other words, an absolute pressure of (760−X) mmHg. In addition,negative pressure that is “less” or “smaller” than X mmHg corresponds topressure that is closer to atmospheric pressure (such as, −40 mmHg isless than −60 mmHg). Negative pressure that is “more” or “greater” than−X mmHg corresponds to pressure that is further from atmosphericpressure (such as, −80 mmHg is more than −60 mmHg). In some embodiments,local ambient atmospheric pressure is used as a reference point, andsuch local atmospheric pressure may not necessarily be, for example, 760mmHg.

The negative pressure range for some embodiments of the presentdisclosure can be approximately −80 mmHg, or between about −20 mmHg and−200 mmHg. Note that these pressures are relative to normal ambientatmospheric pressure, which can be 760 mmHg. Thus, −200 mmHg would beabout 560 mmHg in practical terms. In some embodiments, the pressurerange can be between about −40 mmHg and −150 mmHg. Alternatively apressure range of up to −75 mmHg, up to −80 mmHg or over −80 mmHg can beused. Also in other embodiments a pressure range of below −75 mmHg canbe used. Alternatively, a pressure range of over approximately −100mmHg, or even −150 mmHg, can be supplied by the negative pressureapparatus.

In some embodiments of wound closure devices described herein, increasedwound contraction can lead to increased tissue expansion in thesurrounding wound tissue. This effect may be increased by varying theforce applied to the tissue, for example by varying the negativepressure applied to the wound over time, possibly in conjunction withincreased tensile forces applied to the wound via embodiments of thewound closure devices. In some embodiments, negative pressure may bevaried over time for example using a sinusoidal wave, square wave, or insynchronization with one or more patient physiological indices (such as,heartbeat). Examples of such applications where additional disclosurerelating to the preceding may be found include U.S. Pat. No. 8,235,955,titled “Wound treatment apparatus and method,” issued on Aug. 7, 2012;and U.S. Pat. No. 7,753,894, titled “Wound cleansing apparatus withstress,” issued Jul. 13, 2010. The disclosures of both of these patentsare hereby incorporated by reference in their entirety.

Embodiments of the wound dressings, wound dressing components, woundtreatment apparatuses and methods described herein may also be used incombination or in addition to those described in InternationalApplication No. PCT/IB2013/001469, filed May 22, 2013, published as WO2013/175306 A2 on Nov. 28, 2013, titled “APPARATUSES AND METHODS FORNEGATIVE PRESSURE WOUND THERAPY,” U.S. patent application Ser. No.14/418,908, filed Jan. 30, 2015, published as US 2015/0190286 A1 on Jul.9, 2015, titled “WOUND DRESSING AND METHOD OF TREATMENT,” thedisclosures of which are hereby incorporated by reference in theirentireties. Embodiments of the wound dressings, wound dressingcomponents, wound treatment apparatuses and methods described herein mayalso be used in combination or in addition to those described in U.S.patent application Ser. No. 13/092,042, filed Apr. 21, 2011, publishedas US2011/0282309, titled “WOUND DRESSING AND METHOD OF USE,” and U.S.patent application Ser. No. 14/715,527, filed May 18, 2015, published asUS2016/0339158 A1 on Nov. 24, 2016, titled “FLUIDIC CONNECTOR FORNEGATIVE PRESSURE WOUND THERAPY,” the disclosure of each of which ishereby incorporated by reference in its entirety, including furtherdetails relating to embodiments of wound dressings, the wound dressingcomponents and principles, and the materials used for the wounddressings.

Additionally, some embodiments related to TNP wound treatment comprisinga wound dressing in combination with a pump or associated electronicsdescribed herein may also be used in combination or in addition to thosedescribed in International Application PCT/EP2016/059329 filed Apr. 26,2016, published as WO 2016/174048 on Nov. 3, 2016, entitled “REDUCEDPRESSURE APPARATUS AND METHODS,” the disclosure of which is herebyincorporated by reference in its entirety.

Sensor Enabled Wound Monitoring and Therapy System

FIG. 1A illustrates a wound monitoring and therapy system 10 accordingto some embodiments. The system includes a sensor enabled wound dressing22 connected to a controller 24. As is described herein, the dressing 22can be placed on or in a wound of a patient and can utilize varioussensors embedded or otherwise placed in the dressing 22 to collectmeasurement data from one or more of the wound or areas surrounding thewound, such as the periwound (which can include intact skin). Thecontroller 24 can receive, store, and process data collected by thedressing 22. To facilitate communication, the dressing 22 can includeone or more communication modules, such as one or more antennas asdescribed herein. In some cases, the controller 24 can transmit one ormore of commands and data to the dressing 22.

In some embodiments, wound dressing 22 can be disposable and controller24 can be reusable. In some embodiments, wound dressing 22 can bereusable. In some embodiments, wound dressing 22 can be re-sterilized orotherwise sanitized or disinfected. In some embodiments, controller 24can be disposable. In some embodiments, wound dressing 22 and controller24 can be permanently connected and the combined wound dressing andcontrol box be disposable, or reusable or re-sterilized or otherwisesanitized or disinfected. The controller 24 can be positioned on thewound dressing 22. The controller 24 can be spatially separated from thewound dressing 22, such as by a cable or another wired or wirelesselectrical connection. The controller 24 can include a power source(such as a battery), one or more processors, one or more data storageelements, and a communication device. In some embodiments, thecontroller 24 can include one or more sensors, such as a temperaturesensor or optical sensor to gather information on patient orenvironmental conditions located away from the wound dressing 22. Insome embodiments, the one or more sensors of the controller 24 caninclude an accelerometer, motion sensor or gyroscope.

In some embodiments, the wound dressing 22 can include one or moreindicators to communicate information to a user. The indicators can bevisual, audible, haptic, or tactile. Communicated information caninclude measurement data, wound status, or the like.

The controller 24 can communicate data to a communication device 30 asrequested, periodically, or the like. Communication can be performedover a wired or wireless interface, such as via near field communication(NFC), RFID, or the like when the communication device is placed incommunication range. For example, communication range can be closeproximity, such as within approximately 3 cm or less or more, to thecontroller 24. Communication device 30 can be placed in communicationrange by a clinician, such as during initialization and at the end oftreatment. The controller 24 can respond with data to a command from thecommunication device 30 requesting data. Communication can be performedvia transfer of hardware or data storage, such as one or more memorystorage devices (for example, SD card). In some cases, communication canbe performed non-electronically, such as visually, audibly, ortactilely, and one or more of the controller 24 or communication device30 can provide an interface for such non-electronic communication ofdata.

The communication device 30 can be connected via a wired or wirelessinterface to a computing device 40, such as a personal computer, tablet,smartphone, or the like. For example, wired USB protocol can be used forcommunication of data between devices 30 and 40. As another example,communication of data can be performed via transfer of hardware or datastorage, such as one or more memory storage devices (for example, SDcard). In some cases, communication of data can be performednon-electronically, such as visually, audibly, or tactilely, and one ormore of the communication device 30 or computing device 40 can providean interface for such non-electronic communication of data.

Computing device 40 can further process data collected by the dressing22. For example, the computing device 40 can aggregate data collectedfrom the dressing 22 and perfusion determination device 70, which isconfigured to determine skin perfusion pressure and communicate data tothe computing device 40 via a wired or wireless interface. For example,wired USB protocol can be used for communication between devices 70 and40.

Computing device 40 can be configured to communicate via a wired orwireless interface with a remote computing device 50 that stores andprocesses medical data. In some embodiments, remote computing device 50can be a cloud computing device, which includes one or more of remotestorage, server, processing device, or any means of information storage.For example, remote computing device 50 can process and store medicaldata according with one or more applicable security and privacystandards, such as Health Insurance Portability & Accountability Act(HIPPA), European Union's Directive on Data Protection, or the like.Remote computing device 50 can make data provided by one or more of thecomputing device 40 or the mobile device 60 available for remoteaccessing and viewing, such as on a mobile device 60. In certainimplementations, additional data can be added for storage on the remotecomputing device 50. For example, additional data can be added by themobile device 60 via a dedicated app, web browser interface, or thelike. The remote computing device 50 can process the data from one ormore of the wound dressing 22, perfusion determination device 70, or themobile device and assess or determine treatment plan, such as suggest oradjust one or more treatment therapies.

As described herein, mobile device 60 can take one or more images of apatient's wound. Such data can be transmitted via wired or wirelessinterface to the remote computing device 50. Although a smartphone isillustrated, mobile device 60 can be any suitable computing device thatincludes imaging functionality, such as a camera. Mobile device 60 canalso collect additional data, such as data input by a healthcareprovider in response to a questionnaire.

Various components illustrated in FIG. 1A are described in more detailin other portions of the present disclosure.

FIG. 1B illustrates the use of a wound monitoring and therapy system,such as the system 10, according to some embodiments. As is illustrated,in blocks 1102 and 1104, a user (such as, healthcare provider (HCP)),can provide information regarding patient's medical history andlifestyle. Such information can be provided via the mobile device 60 forstorage on the remote computing device 50 as described herein (such as,via an app). In block 1106, assessment of the wound can be performed.For example, images of the wound can be taken by the mobile device 60and uploaded to the remote computing device 50 as described herein.Alternatively or additionally, skin perfusion pressure can be measuredby the device 70 and uploaded to the remote computing device 50 asdescribed herein.

In block 1108, treatment decision of the user can be recorded. Forexample, one or more treatment therapies can be selected, such asnegative pressure wound therapy. In block 1110, additional images of theclean and, if applicable, debrided wound can be taken and uploaded tothe remote computing device. In block 1112, wound dressing 22 can beplaced in or on wound of the patient. In block 1114, controller 24 canbe connected to the wound dressing 22, in cases where the wound dressingand controller are separate. The wound dressing can be initialized asdescribed herein. In block 1116, one or more selected therapies can beapplied. In block 1118, images of the wound covered by the wounddressing 22 can be taken and uploaded. In block 1120, measurement datafrom the wound dressing 22 can be collected and stored, as describedherein. This step can be performed as many times as suitable while thewound dressing 22 is applied to the patient. Upon completion of therapy,in block 1122, measurement data can be uploaded to the remote computingdevice 50 as described herein. In block 1124, images of healed wound canbe taken.

In some embodiments, one or more images of the wound can be processedusing Eulerian magnification techniques described in U.S. ProvisionalPatent Application No. 62/506,524, titled NEGATIVE PRESSURE WOUNDTHERAPY SYSTEM USING EULERIAN VIDEO MAGNIFICATION, filed on 15 May 2017and 62/506,551, titled WOUND ANALYSIS DEVICE AND METHOD, filed on 15 May2017, each of which is incorporated by reference in its entirety.Eulerian magnification techniques can be implemented by any of thecomponents of the system 10, such as the mobile device 60 or remotecomputing device 50.

Sensor Enabled Wound Dressing

FIG. 1C illustrates sensor enabled wound dressing 22 according to someembodiments. As described herein, the wound dressing 22 can include asubstantially flexible wound contact layer, which can include one ormore features of any of the wound contact layers described herein. Thewound dressing 22 can include any of the wound dressing layers describedherein. The entire wound dressing 22 can be substantially flexible. Asis illustrated, one or more sensors 26 connected by one or moreelectrical connections or tracks 27 are positioned on or embedded in thewound dressing 22. For example, the one or more sensors and connectionscan be positioned on the wound contact layer. Also illustrated is aconnector 28 for connecting to wound dressing 22 to the controller 24.The connector 28 includes one or more electrical connections or tracks.In some implementations, borders or edges of the wound contact layer canbe smoothed by cuts, have smooth contours, include fibers, and/or thelike to improve patient comfort.

In some implementations, borders or edges of the wound contact layer canbe smoothed by cuts, have smooth contours, include fibers, and/or thelike to improve patient comfort.

In some embodiments, the dressing can include one or more antennas forwireless communication. For example, one or more antennas can be printedas one or more connections or traces on the wound contact layer. The oneor more antennas can be used to communicate measurement data collectedby the one or more sensors without the controller 24. The one or moreantennas can additionally be used to receive power wirelessly from apower source. In certain cases, the one or more antenna traces can bepositioned on a substantially non-stretchable material (as describedherein) such that the resonant frequencies of the one or more antennasremain fixed when the wound dressing 22 is placed under stress when inuse on a patient. Fixing the one or more resonant frequencies can beadvantageous for certain communication protocols, such as RFID.

In some embodiments, one or more sensors of the wound dressing 22 or anyother wound dressing disclosed herein can measure one or more ofimpedance, capacitance, electrical sensing, temperature, pH, pressure(such as, by using a strain gauge), elasticity of tissue (such as, byusing an ultrasound sensor, piezoelectric transducer, or the like, bloodflow (such as, by measuring the Doppler effect), color, or light. One ormore sensors can be electronic or non-electronic. Examples ofnon-electronic sensors include sensors that change color as a functionof pH or when stretched, strained, or otherwise subjected to pressure.Measurements of such sensors can be obtained through visual monitoring,which can be performed automatically, such as by using a camera or byusing one or more optical sensors.

In certain implementations, impedance measurements can be made utilizinga 4-point probe measurement as shown in FIG. 1D. A drive signal, such asAC drive signal, can be generated across drive pads 1002 and the voltagemeasurement can be made across separate measurement pads 1004. The padscan be positioned as illustrated in FIG. 1E. Eight measurement pads 1004can be laid out as the corners of two concentric squares. The outersquare can have approximately 80 mm side or any other suitabledimension. The inner square can have approximately 30 mm side or anyother suitable dimension.

In some implementations, a complex voltage measurement can be taken asfollows:

TABLE 1 Impedance measurement Between pads 1 2 1 3 1 7 2 4 2 8 3 4 3 5 36 4 5 4 6 5 6 5 7 6 8 7 8Complex voltage measurement can identify the maximum and minimumvoltages and the phase angle (or time) behind the drive signal.Additional details of impedance measurement are described in one or moreof U.S. Provisional Patent Application No. 62/536,774, titled “SkewingPads for Impedance Measurement,” filed on 25 Jul. 2017, or InternationalPatent Application No. PCT/EP2018/069886, titled “Skewing Pads forImpedance Measurement,” filed on 23 Jul. 2018, each of which isincorporated by reference in its entirety.

In some embodiments, impedance measurement is based on an ACmeasurement. An excitation signal can be coupled to the tissuecapacitively through a sensor or pad with insulating coating. A secondsimilar electrode can be placed some distance away and connected toground. By applying an excitation signal, an AC current flows throughthe tissue between the pads.

Second pair(s) of electrodes can be placed between the excitationelectrodes, and can be used to sense voltage. These two electrodes caneach be connected to one or more high impedance amplifiers, whoseoutputs can be fed to a differential amplifier. By measuring this outputvoltage, and dividing by the excitation current, the impedance betweenthe measurement electrodes can be measured.

As is illustrated in FIG. 1F, voltage and current can be detected usinga pair of lock-in amplifiers. As the measured impedance may berelatively high, particularly at the electrode to tissue junction, itmay be advantageous that the measurement electrode amplifiers have highinput impedance. First stage amplifiers can be chosen to have high inputimpedance. These can be configured as non-inverting amplifiers in orderto take advantage of this high input impedance. The low-frequency gaincan be rolled down using capacitors C1, C2, C3 and C4, as is illustratedin FIG. 1F.

In some cases, for single supply operation, the non-inverting input mayneed to be biased at mid-rail. The biasing may also need to provide a DCpath for the input bias current of the op-amp. While this could be doneusing a resistive divider at the non-inverting input, it may lead to thefollowing:

1. The bias network lowers the input impedance unless resistors of theorder of the op-amp input impedance are used (and resistors of thisvalue are impractically large).

2. Large bias resistors contribute a large thermal noise component whichswamps the input noise voltage of the op-amp, reducing the overallsignal-to-noise ratio.

In some embodiments, instead of using resistors, the input bias isachieved using a pair of reverse biased diodes D1, D2, D3, and D4 asillustrated in FIG. 1F. The reverse biased diode presents a very highimpedance (determined by the reverse leakage), without the high thermalnoise contribution. Diode with a very low reverse leakage can be chosen.The reverse leakage also provides the DC path for the op-amp biascurrent.

In some embodiments, one or more temperature sensors provide a map ofthe wound. As is illustrated in FIG. 1G, an array of 25 (or more orless) temperature sensors 1010 in a 5-by-5 grid can be used. Thetemperature sensors can be positioned equidistant with respect to eachother.

In some embodiments, optical sensors (for example, color sensors, red,green, and blue (RGB) sensors, red, green, blue, and clear (RGBC)sensors, or red, green, blue, and white (RGBW) sensors) can be includedin the wound dressing 22 for obtaining one or more optical measurements.Optical sensors can be located in various positions throughout the wounddressing. In some embodiments, RGB sensors can be used for opticalmeasurements. As is illustrated in FIG. 1H, RGB sensors 1020 canincorporate one sensor at the center of the measurement area, four at amid-distance from the center (such as, approximately 20 mm from thecenter) and four around the outer edges (such as, approximately 35 mmfrom the center). Each of the nine RGB sensors can incorporate onesensor one and one white LED.

Any distance, signal value, or the like described in the foregoing isprovided for illustrative purposes. In some embodiments, other suitabledistances, signal value, or the like can be utilized depending on thesize of the measurement area, particular measurements of interest, orthe like.

Cybersecurity

A wound monitoring and therapy system 10 may incorporate one or morecybersecurity techniques. For example, the communication device 30 mayallow the system 10 to transmit data via a wired or wirelesscommunications network, such as a NFC or cellular network. For instance,NFC can be used for communication with the controller 24 and cellularnetwork can be used for communication with the remote computing device50. The communications network can provide access to the Internet.

In some embodiments, the system 10 may implement various cybersecuritymeasures. In certain implementations, when the dressing 22 is connectedto the controller 24 (such as, plugged into the controller 24), thecontroller can initialize. This may include the controller 24 performingone or more of the following:

-   -   Powering on. For example, continuous power to the controller 24        and the wound dressing 22 can be established (such as, via a        latching circuit).    -   Generating a device clock. For example, device clock time can        start from zero, random number, a unique number, such as a        hardware identification number, or the like at initiation and        will count up whenever the controller 24 is under power. If        power is interrupted, the count may be re-established from the        previous clock time before power interruption. In some        embodiments, device clock is not a real-time clock, but is an        arbitrary value.    -   Performing a power-on self-test (POST) and other testing.

In some implementations, POST can determine whether one or more sensorson the dressing 22 are functioning within proper ranges. For example,functioning of one or more temperature sensors, oxygen sensors, pHsensors, optical sensors, or any additional sensor discussed herein canbe tested. Testing may include comparing the results of the sensortest(s) to threshold value(s) or range(s). If it is determined that oneor more sensors measurements fall outside threshold value(s) orrange(s), indication or alert can be generated. Alert can be visual,audio, tactile, or the like. In some embodiments, the alert may indicatewhich sensor is experiencing an error state. If the one or more sensorsof the dressing 22 passes the POST, one or more of sensor data or deviceclock time can be recorded. In some instances, one or more components ofthe system 10 may indicate to the user that sensors are functioningwithin proper ranges. POST may be performed every time the dressing 22is connected or re-connected to the controller 24, periodically when thedressing 22 is connected to the controller 24, or the like.

In some embodiments, proper memory capability can be verified as part ofinitialization. For example, one or more components of the system 10(such as the computing device 40 or the controller 24) may determine ifsufficient memory is remaining upon connection of the dressing 22 to thecontroller 24 or upon communication of data to the communication device30. The controller 24 or computing device 40, in some instances, maycompare the current remaining memory of the controller 24, communicationdevice 30, or computing device 40 to one or more thresholds. If thecurrent remaining memory of one or more components of the system 10 isbelow the one or more thresholds, low memory alert can be generated.

In certain implementations, proper capacity of a power source can beverified as part of initialization. This can be performed similarly tothe memory testing described herein and a low power alert can begenerated. As described herein, a sensor enabled wound dressing 22connected to a controller 24 may be placed on or in a wound and cancollect measurement data from the wound. At least one of the dressing 22or controller 24 can store the collected measurement data or transmitthe measurement data to a computing device 40, via a communicationdevice 30. The dressing 22 or controller 24 may be configured tointeract, via a wired or wireless interface, with the communicationsdevice 30 to transmit the collected measurement data. The communicationdevice 30 may be connected to a computing device 40 (described herein).

In some embodiments, to facilitate security and patient confidentiality,communication between the controller 24 and the communication device 30can be one-way communication of data to the communication device 30. Asdescribed herein, such communication can be performed wirelessly, suchas via NFC when the communication device 30 is placed in communicationrange of the controller 24.

In some embodiments, communication between the controller 24 and thecommunication device 30 includes transmission of the device clock timealong with data measured by the wound dressing 22 to the communicationdevice 30. For security and patient confidentiality, in certainimplementations, device clock time may not reflect real time clock. Inaddition, information identifying the patient may not be stored on thewound dressing 22, controller 24, or the communication device 30. Whilethe controller 24 may store a unique identification number (such as,hardware identification number), this information alone may not besufficient to identify the patient as the controller 24 may be used withmultiple patients. Without real time clock, measurement data collectedby the wound dressing 22 may, at a minimum, remain anonymous andconfidential even if the system is hacked.

In some embodiments, real time clock may be known by one or more of thecomputing device 40 or remote computing device 50. For example, inresponse to measurement data and device clock time being transmittedfrom the communication device 30 to the computing device 40, thecomputing device 40 can correlate device clock time with real time basedon the received device clock time and real time clock time. For example,the computing device 40 can, during initialization, receive time of thedevice clock. During subsequent transmission of measurement data alongwith device clock time, remote computing device can determine elapsedtime relative to the initial transmission based on comparison of theinitial time of the device clock and currently received time of thedevice clock associated with the measurement data. For example, thecomputing device 40 can subtract the initial time of the device clockfrom the currently received time of the device clock to determine theelapsed time.

Computing device 40 can be a secure system, such as a medical gradecomputing device. Computing device 40 can store the data temporarily fortransmission to the remote computing device 50, which may correlate thedata with patient identification to associate the data to a particularpatient. After successfully transmitting the data to the remotecomputing device 50, computing device 40 can delete the data fromstorage. As described herein, remote computing device 50 can be a securesystem. Remote computing device 50 may store measurement data associatedwith the particular patient along with real time of when one or moremeasurements were taken. Patient identification and other related data,such as patient photo(s), patient data, clinician identification, or thelike, can be provided to the remote computing device 50 by the mobiledevice 60. Communication between the mobile device 60 and the remotecomputing device 50 can be secure, such as encrypted. In some instances,an app or another program is provided on the mobile device 60 forcommunicating with the remote computing device 50.

In certain cases, the controller 24 can transmit most recently measureddata to the computing device 40. The controller 24 can additionallytransmit its unique identification number, such as the hardwareidentification number. Additional data, such as checksum, errorcorrection, or the like can be transmitted.

In some implementations, the controller 24 transmits most recentlymeasured data after initialization. If such initial transmission issuccessful, the computing device 40 can indicate to the controller 24that additional measurement data can be collected by the wound dressing22 as applicable. If the initial transmission is not successful, wounddressing 22 may not be permitted to log additional measurements untilcommunication with the computing device 40 has been successfullyestablished. In some cases, inability to successfully complete theinitial transmission may be associated with the system being hacked. Ifthe initial transmission is successful, in some embodiments, allmeasurement data since previous transmission can be uploaded by thecontroller 24 to the communication device 30 at a suitable time, such aswhen the communication device is placed in communication range of thecontroller 24. Such transmission can be performed after end oftreatment.

In some implementations, data transmitted between various components ofthe system can be encrypted. For example, measurement data stored by thecontroller 24 can be encrypted.

The dressing 22 or the controller 24 may be disconnected from thecommunications device 30. One or more components of the system 10, insome embodiments, may alert a user once the dressing 22 or thecontroller are disconnected. For example, the dressing 22, controller24, communication device 30, or computing device 40 may provide an alertthat one or more components of the system 10 are disconnected. In someinstances, the computing device 40 can record a real time clock timewhen the dressing 22 or controller 24 are disconnected.

As described herein, measurement data recorded from the dressing 22 maybe recorded and stored in one or more components of the system 10, suchas the controller 24. The data may be stored in accordance with asecurity protocol, which may safeguard patient privacy andconfidentiality. In some embodiments, the recorded measurement data willnot include any patient identifying information. The security protocolmay include correlating the recorded measurement data with an arbitraryvalue. In some instances, the arbitrary value may include a device clocktime from a non-real time clock indicating the time at which measurementdata was obtained. The measurement data may be transferred via thecommunications device 30 to the computing device 40. In someembodiments, the communication device 30 may only permit one-waycommunication between the controller 24 and the computing device 40.Alternatively, the communication device 30 may permit the transfer ofinformation to and from the controller 24 and the computing device 40.The measurement data transferred to the computing device 40 may beencrypted, as described herein. In some instances, the recordedmeasurement data may only be correlated with patient-identifyinginformation once the recorded measurement data is transferred to asecure computing device, such as the remote computing device 50.

In some embodiments, data taken by the perfusion determination device 70is communicated to the computing device 40 similarly without patientidentifying information and real time clock information. Computingdevice 40 can similarly process the data as described herein.

Measuring Skin Perfusion Pressure

In some embodiments, a perfusion determination device, such as thedevice 70, includes one or more of the following features. The devicecan include a sensor module comprising a first sensor in the form of aforce sensor for sensing a force transmitted through the sensor moduleto a measurement or target area, such as the patient's arm or leg and asecond sensor in the form of an optical sensor for sensing a parameterwhich corresponds to the amount of blood perfusion in the skin tissue ofthe target area underneath the sensor module. In certainimplementations, the optical sensor can be a pulse sensor, but othersuitable sensors may be used such as a reflective pulse oximeter sensoror the like. The force sensor can be a thin-film micro-force sensor witha diameter of 15 mm and a force range of 45N. The force sensor can alsocomprise associated read-out electronics. The force sensor can bedisposed on an upper portion of the optical sensor, and the opticalsensor can be arranged such that it faces away from the force sensortowards the target area. Force and optical sensors can be connectedelectrically, such as by using one or more wires.

In some implementations, in use, the sensor module can be placed againstthe target area of a patient so that a lower portion of a housing of thesensor module, which can be open or transparent, is adjacent the targetarea of skin tissue. The lower portion of the housing may be in contactwith the target area. The skin perfusion pressure determination devicecan then be secured to the measurement area. Outputs from the forcesensor and the optical sensor can be monitored and, if applicable,displayed or otherwise provided to a user.

As is illustrated in FIG. 6 , the upper trace is a photoplethysmogram(PPG) which provides an indication of the amount of light emitted by theoptical sensor that is absorbed by the skin tissue at the target area(i.e. the trace is inversely proportional to the amount of lightreflected by the skin tissue at the target area and received by aphotodiode). Therefore, a relatively large amount of blood in the skintissue, which absorbs a relatively large amount of light emitted by theoptical sensor, produces a relatively high output trace value, and viceversa. Of course, the trace could be inverted such that the amount oflight reflected by the skin tissue is plotted in which case, a largeamount of blood within the skin tissue would produce a relatively lowoutput trace value.

The upper trace will typically have a pulsatile component and anon-pulsatile component. The pulsatile component represents lightabsorbed by pulsatile arterial blood whereas the non-pulsatile componentrepresents light absorbed by non-pulsatile arterial blood, venous bloodand skin tissue. The pulsatile component arises due to the change inblood volume caused by the pressure pulse of the cardiac cycle pushingblood through the blood vessels and capillaries and is thereforeassociated with blood flow. The pulsatile component can therefore bemonitored to obtain an indication of the amount of blood perfusion inthe underlying tissue.

The amount of light absorbed by the skin tissue initially once the skinperfusion pressure determination device has been secured to the targetarea is shown between times t₁ and t₂ of the upper trace in FIG. 6 .Each peak represents a pulse of arterial blood through the skin tissueat the target area.

Time t₂ is the time at which a skin perfusion pressure measurement iscommenced.

In some embodiments, in use, a user, such as healthcare provider,presses the sensor module against the target area to occlude the bloodvessels within the tissue below the target area. The amount of force isincreased until the pulsatile component of the trace drops below apredetermined level or ceases to be evident, as shown at time t₃. Oncethe trace drops below the predetermined level, the user continues tohold the sensor module against the target area to ensure that thepulsatile arterial blood flow has ceased in the tissue at the targetarea, as shown between times t₃ and t₄. In the example shown, thereremains a non-zero noise component of the trace which fluctuates at alevel below the predetermined level. At time t₄, the user begins toreduce the force applied to the sensor module slowly until time t₅ atwhich time the sensor module has been released completely and pulsatilearterial blood flow in the tissue at the target area is completelyrestored.

The force exerted by the user on the tissue at the target area via thesensor module is recorded by the lower trace. As can be seen from thelower trace, no force is recorded between times t₁ and t₂. The forceincreases relatively rapidly between times t₂ and t₃ as the user pressesthe sensor module against the target area of the patient and thenplateaus while the user holds the sensor module against the target areabetween times t₃ and t₄. As the user begins to slowly release the sensormodule at time t₄, the applied force reduces steadily back to zero attime t₅ and pulsatile arterial blood flow returns to the skin tissue.

Pulsatile arterial blood flow returns when the blood pressure issufficient to overcome the occlusion pressure on the blood vesselswithin the tissue which is applied by the user pressing on the sensormodule. The return of blood flow is represented by a return of thepulsatile component in the upper trace, as shown at time t_(SPP).Different criteria can be used to determine the return of pulsatilearterial blood flow. For example, return of blood flow could bedetermined by the return of the value of the upper trace to apredetermined threshold I_(SPP) value such as a value greater than amaximum expected noise value. Alternatively, the threshold value I_(SPP)may be a value that is determined based on the pulse amplitude observedbefore a force is applied to occlude the blood vessels (i.e. the pulseamplitude between times t₁ and t₂). In one example, a threshold valueI_(SPP) may be used which is a predetermined percentage of the pulseamplitude observed before a force is applied to occlude the bloodvessels. Other algorithms may be used to determine return of thepulsatile component of the trace.

The magnitude of the force F_(SPP) of the lower trace at time t_(SPP) isthen recorded. The recorded force F_(SPP) can subsequently be used todetermine a skin perfusion pressure. This may be done by calculation,look-up tables or based on a pre-calibration of the force sensor. Forexample, if the contact area of the portion of the sensor module pressedagainst the skin tissue is known, the pressure applied to the skintissue can be calculated. In this instance, the target area correspondsto the contact area of the sensor module.

In some embodiments, the contact area of the sensor module can becircular and planar. In some embodiments, the contact area of the sensormodule can be circular and convex, and the resulting domed structure canbe symmetric or asymmetric. The structure can be of a single side, suchas the contact area that would be made onto skin by a dome or it caninclude of multiple faces, such as a convex polyhedron (which can besimilar to the structures seen with geodesic domes, footballs, skeletalformula of buckminsterfullerene). In some embodiments, ridged orscalloped domes and structures can be used. In some embodiments, amixture of the above may be employed, such as a flat window for opticalmeasurements in the centre of the contact area, which can be surroundedby a convex domed surface. The internal radius of the dome can bedesigned to allow even loading of force, and thus pressure, across thearea of skin that is under assessment. In some embodiments, the contactarea of the sensor module is circular and has a diameter of 10 mm andtherefore a surface area of approximately 80 mm². The larger the contactarea, the greater the force required to stop blood flow. The smaller thecontact area, the greater the fluctuations in pressure caused byfluctuations in the force applied so that, for very small contact areasit becomes difficult for a user to release the applied force in acontrolled manner in order to determine the force at which blood flowreturns. A very small contact area can also make it difficult for anaccurate reading to be taken by the blood perfusion sensor. The contactarea of the sensor module may therefore be between 1 mm² and 1000 mm²,for example between 10 mm² and 400 mm².

A benefit of the arrangement is that contemporaneous measurements of thepressure exerted by the sensor module on the target area and the amountof blood perfusion are made at the target area. The measurements can betaken and recorded simultaneously to produce an accurate and reliablemeasurement of blood perfusion pressure at a desired location on apatient's body.

Measurement of skin perfusion pressure may be performed as a singlemeasurement or determined from trends evident from repeated measurementsover time. Such measurements may be used to aid the prediction of woundhealing.

Additional details regarding measurement of skin perfusion pressure aredescribed in International Application No. PCT/EP2018/055940, filed on 9Mar. 2018, which is incorporated by reference in its entirety.

Negative Pressure Wound Therapy System

FIG. 2A illustrates an embodiment of a negative or reduced pressurewound treatment (or TNP) system 100 comprising a wound filler 130 placedinside a wound cavity 110, the wound cavity sealed by a wound cover 120.The wound filler 130 in combination with the wound cover 120 can bereferred to as a wound dressing. The wound dressing may include one ormore sensors as described herein. A single or multi lumen tube orconduit 140 is connected the wound cover 120 with a pump assembly 150configured to supply reduced pressure. The wound cover 120 can be influidic communication with the wound cavity 110. In any of the systemembodiments disclosed herein, as in the embodiment illustrated in FIG.2A, the pump assembly can be a canisterless pump assembly (meaning thatexudate is collected in the wound dressing or is transferred via tube140 for collection to another location). However, any of the pumpassembly embodiments disclosed herein can be configured to include orsupport a canister. Additionally, in any of the system embodimentsdisclosed herein, any of the pump assembly embodiments can be mounted toor supported by the dressing, or adjacent to the dressing.

The wound filler 130 can be any suitable type, such as hydrophilic orhydrophobic foam, gauze, inflatable bag, and so on. The wound filler 130can be conformable to the wound cavity 110 such that it substantiallyfills the cavity. The wound cover 120 can provide a substantially fluidimpermeable seal over the wound cavity 110. The wound cover 120 can havea top side and a bottom side, and the bottom side adhesively (or in anyother suitable manner) seals with wound cavity 110. The conduit 140 orlumen or any other conduit or lumen disclosed herein can be formed frompolyurethane, PVC, nylon, polyethylene, silicone, or any other suitablematerial.

Some embodiments of the wound cover 120 can have a port (not shown)configured to receive an end of the conduit 140. For example, the portcan be Renays Soft Port available from Smith & Nephew. In otherembodiments, the conduit 140 can otherwise pass through or under thewound cover 120 to supply reduced pressure to the wound cavity 110 so asto maintain a desired level of reduced pressure in the wound cavity. Theconduit 140 can be any suitable article configured to provide at least asubstantially sealed fluid flow pathway between the pump assembly 150and the wound cover 120, so as to supply the reduced pressure providedby the pump assembly 150 to wound cavity 110.

The wound cover 120 and the wound filler 130 can be provided as a singlearticle or an integrated single unit. In some embodiments, no woundfiller is provided and the wound cover by itself may be considered thewound dressing. The wound dressing may then be connected, via theconduit 140, to a source of negative pressure, such as the pump assembly150. The pump assembly 150 can be miniaturized and portable, althoughlarger conventional pumps such can also be used.

The wound cover 120 can be located over a wound site to be treated. Thewound cover 120 can form a substantially sealed cavity or enclosure overthe wound site. In some embodiments, the wound cover 120 can beconfigured to have a film having a high water vapour permeability toenable the evaporation of surplus fluid, and can have a superabsorbingmaterial contained therein to safely absorb wound exudate. It will beappreciated that throughout this specification reference is made to awound. In this sense it is to be understood that the term wound is to bebroadly construed and encompasses open and closed wounds in which skinis torn, cut or punctured or where trauma causes a contusion, or anyother surficial or other conditions or imperfections on the skin of apatient or otherwise that benefit from reduced pressure treatment. Awound is thus broadly defined as any damaged region of tissue wherefluid may or may not be produced. Examples of such wounds include, butare not limited to, acute wounds, chronic wounds, surgical incisions andother incisions, subacute and dehisced wounds, traumatic wounds, flapsand skin grafts, lacerations, abrasions, contusions, burns, diabeticulcers, pressure ulcers, stoma, surgical wounds, trauma and venousulcers or the like. The components of the TNP system described hereincan be particularly suited for incisional wounds that exude a smallamount of wound exudate.

Some embodiments of the system are designed to operate without the useof an exudate canister. Some embodiments can be configured to support anexudate canister. In some embodiments, configuring the pump assembly 150and tubing 140 so that the tubing 140 can be quickly and easily removedfrom the pump assembly 150 can facilitate or improve the process ofdressing or pump changes, if necessary. Any of the pump embodimentsdisclosed herein can be configured to have any suitable connectionbetween the tubing and the pump.

The pump assembly 150 can be configured to deliver negative pressure ofapproximately −80 mmHg, or between about −20 mmHg and 200 mmHg in someimplementations. Note that these pressures are relative to normalambient atmospheric pressure thus, −200 mmHg would be about 560 mmHg inpractical terms. The pressure range can be between about −40 mmHg and−150 mmHg. Alternatively a pressure range of up to −75 mmHg, up to −80mmHg or over −80 mmHg can be used. Also a pressure range of below −75mmHg can be used. Alternatively a pressure range of over approximately−100 mmHg, or even 150 mmHg, can be supplied by the pump assembly 150.

In operation, the wound filler 130 is inserted into the wound cavity 110and wound cover 120 is placed so as to seal the wound cavity 110. Thepump assembly 150 provides a source of a negative pressure to the woundcover 120, which is transmitted to the wound cavity 110 via the woundfiller 130. Fluid (such as, wound exudate) is drawn through the conduit140, and can be stored in a canister. In some embodiments, fluid isabsorbed by the wound filler 130 or one or more absorbent layers (notshown).

Wound dressings that may be utilized with the pump assembly and otherembodiments of the present application include Renasys-F, Renasys-G,Renasys AB, and Pico Dressings available from Smith & Nephew. Furtherdescription of such wound dressings and other components of a negativepressure wound therapy system that may be used with the pump assemblyand other embodiments of the present application are found in U.S.Patent Publication Nos. 2011/0213287, 2011/0282309, 2012/0116334,2012/0136325, and 2013/0110058, which are incorporated by reference intheir entirety. In other embodiments, other suitable wound dressings canbe utilized.

Wound Dressing Overview

FIG. 2B illustrates a cross-section through a wound dressing 155according to some embodiments. FIG. 2B also illustrates a fluidicconnector 160 according to some embodiments. The wound dressing 155 canbe similar to the wound dressing described in International PatentPublication WO2013175306 A2, which is incorporated by reference in itsentirety. Alternatively, the wound dressing 155 can be any wounddressing embodiment disclosed herein or any combination of features ofany number of wound dressing embodiments disclosed herein, can belocated over a wound site to be treated. The wound dressing 155 may beplaced as to form a sealed cavity over the wound, such as the woundcavity 110. In some embodiments, the wound dressing 155 includes a topor cover layer, or backing layer 220 attached to an optional woundcontact layer 222, both of which are described in greater detail below.These two layers 220, 222 can be joined or sealed together so as todefine an interior space or chamber. This interior space or chamber maycomprise additional structures that may be adapted to distribute ortransmit negative pressure, store wound exudate and other fluids removedfrom the wound, and other functions which will be explained in greaterdetail below. Examples of such structures, described below, include atransmission layer 226 and an absorbent layer 221.

As used herein the upper layer, top layer, or layer above refers to alayer furthest from the surface of the skin or wound while the dressingis in use and positioned over the wound. Accordingly, the lower surface,lower layer, bottom layer, or layer below refers to the layer that isclosest to the surface of the skin or wound while the dressing is in useand positioned over the wound.

The wound contact layer 222 can be a polyurethane layer or polyethylenelayer or other flexible layer which is perforated, for example via a hotpin process, laser ablation process, ultrasound process or in some otherway or otherwise made permeable to liquid and gas. The wound contactlayer 222 has a lower surface 224 (for example, facing the wound) and anupper surface 223 (for example, facing away from the wound). Theperforations 225 can comprise through holes in the wound contact layer222 which enable fluid to flow through the layer 222. The wound contactlayer 222 helps prevent tissue ingrowth into the other material of thewound dressing. In some embodiments, the perforations are small enoughto meet this requirement while still allowing fluid to flowtherethrough. For example, perforations formed as slits or holes havinga size ranging from 0.025 mm to 1.2 mm are considered small enough tohelp prevent tissue ingrowth into the wound dressing while allowingwound exudate to flow into the dressing. In some configurations, thewound contact layer 222 may help maintain the integrity of the entiredressing 155 while also creating an air tight seal around the absorbentpad in order to maintain negative pressure at the wound. In someembodiments, the wound contact layer is configured to allowunidirectional or substantially one-way or unidirectional flow of fluidthrough the wound contact layer when negative pressure is applied to thewound. For example, the wound contact layer can permit fluid to flowaway from the wound through the wound contact layer, but not allow fluidto flow back toward the wound. In certain case, the perforations in thewound contact layer are configured to permit such one-way orunidirectional flow of fluid through the wound contact layer.

Some embodiments of the wound contact layer 222 may also act as acarrier for an optional lower and upper adhesive layer (not shown). Forexample, a lower pressure sensitive adhesive may be provided on thelower surface 224 of the wound dressing 155 whilst an upper pressuresensitive adhesive layer may be provided on the upper surface 223 of thewound contact layer. The pressure sensitive adhesive, which may be asilicone, hot melt, hydrocolloid or acrylic based adhesive or other suchadhesives, may be formed on both sides or optionally on a selected oneor none of the sides of the wound contact layer. When a lower pressuresensitive adhesive layer is utilized may be helpful to adhere the wounddressing 155 to the skin around a wound site. In some embodiments, thewound contact layer may comprise perforated polyurethane film. The lowersurface of the film may be provided with a silicone pressure sensitiveadhesive and the upper surface may be provided with an acrylic pressuresensitive adhesive, which may help the dressing maintain its integrity.In some embodiments, a polyurethane film layer may be provided with anadhesive layer on both its upper surface and lower surface, and allthree layers may be perforated together.

A layer 226 of porous material can be located above the wound contactlayer 222. This porous layer, or transmission layer, 226 allowstransmission of fluid including liquid and gas away from a wound siteinto upper layers of the wound dressing. In particular, the transmissionlayer 226 can ensure that an open air channel can be maintained tocommunicate negative pressure over the wound area even when theabsorbent layer has absorbed substantial amounts of exudates. The layer226 can remain open under the typical pressures that will be appliedduring negative pressure wound therapy as described above, so that thewhole wound site sees an equalized negative pressure. The layer 226 maybe formed of a material having a three dimensional structure. Forexample, a knitted or woven spacer fabric (for example Baltex 7970 weftknitted polyester) or a non-woven fabric could be used.

In some embodiments, the transmission layer 226 comprises a 3D polyesterspacer fabric layer including a top layer (that is to say, a layerdistal from the wound-bed in use) which is a 84/144 textured polyester,and a bottom layer (that is to say, a layer which lies proximate to thewound bed in use) which is a 10 denier flat polyester and a third layerformed sandwiched between these two layers which is a region defined bya knitted polyester viscose, cellulose or the like monofilament fiber.Other materials and other linear mass densities of fiber could of coursebe used.

Whilst reference is made throughout this disclosure to a monofilamentfiber it will be appreciated that a multistrand alternative could ofcourse be utilized. The top spacer fabric thus has more filaments in ayarn used to form it than the number of filaments making up the yarnused to form the bottom spacer fabric layer.

This differential between filament counts in the spaced apart layershelps control moisture flow across the transmission layer. Particularly,by having a filament count greater in the top layer, that is to say, thetop layer is made from a yarn having more filaments than the yarn usedin the bottom layer, liquid tends to be wicked along the top layer morethan the bottom layer. In use, this differential tends to draw liquidaway from the wound bed and into a central region of the dressing wherethe absorbent layer 221 helps lock the liquid away or itself wicks theliquid onwards towards the cover layer where it can be transpired.

In some embodiments, to improve the liquid flow across the transmissionlayer 226 (that is to say perpendicular to the channel region formedbetween the top and bottom spacer layers, the 3D fabric may be treatedwith a dry cleaning agent (such as, but not limited to, PerchloroEthylene) to help remove any manufacturing products such as mineraloils, fats or waxes used previously which might interfere with thehydrophilic capabilities of the transmission layer. An additionalmanufacturing step can subsequently be carried in which the 3D spacerfabric is washed in a hydrophilic agent (such as, but not limited to,Feran Ice 30 g/I available from the Rudolph Group). This process stephelps ensure that the surface tension on the materials is so low thatliquid such as water can enter the fabric as soon as it contacts the 3Dknit fabric. This also aids in controlling the flow of the liquid insultcomponent of any exudates.

A layer 221 of absorbent material can be provided above the transmissionlayer 226. The absorbent material, which comprise a foam or non-wovennatural or synthetic material, and which may optionally comprise asuper-absorbent material, forms a reservoir for fluid, particularlyliquid, removed from the wound site. In some embodiments, the layer 221may also aid in drawing fluids towards the backing layer 220.

The material of the absorbent layer 221 may also prevent liquidcollected in the wound dressing 155 from flowing freely within thedressing, and can act so as to contain any liquid collected within thedressing. The absorbent layer 221 also helps distribute fluid throughoutthe layer via a wicking action so that fluid is drawn from the woundsite and stored throughout the absorbent layer. This helps preventagglomeration in areas of the absorbent layer. The capacity of theabsorbent material must be sufficient to manage the exudates flow rateof a wound when negative pressure is applied. Since in use the absorbentlayer experiences negative pressures the material of the absorbent layeris chosen to absorb liquid under such circumstances. A number ofmaterials exist that are able to absorb liquid when under negativepressure, for example superabsorber material. The absorbent layer 221may typically be manufactured from ALLEVYN™ foam, Freudenberg 114-224-4or Chem-Posite™ 11C-450. In some embodiments, the absorbent layer 221may comprise a composite comprising superabsorbent powder, fibrousmaterial such as cellulose, and bonding fibers. In a some embodiments,the composite is an airlaid, thermally-bonded composite.

In some embodiments, the absorbent layer 221 is a layer of non-wovencellulose fibers having super-absorbent material in the form of dryparticles dispersed throughout. Use of the cellulose fibers introducesfast wicking elements which help quickly and evenly distribute liquidtaken up by the dressing. The juxtaposition of multiple strand-likefibers leads to strong capillary action in the fibrous pad which helpsdistribute liquid. In this way, the super-absorbent material isefficiently supplied with liquid. The wicking action also assists inbringing liquid into contact with the upper cover layer to aid increasetranspiration rates of the dressing.

An aperture, hole, or orifice 227 can be provided in the backing layer220 to allow a negative pressure to be applied to the dressing 155. Insome embodiments, the fluidic connector 160 is attached or sealed to thetop of the backing layer 220 over the orifice 227 made into the dressing155, and communicates negative pressure through the orifice 227. Alength of tubing may be coupled at a first end to the fluidic connector160 and at a second end to a pump unit (not shown) to allow fluids to bepumped out of the dressing. Where the fluidic connector is adhered tothe top layer of the wound dressing, a length of tubing may be coupledat a first end of the fluidic connector such that the tubing, orconduit, extends away from the fluidic connector parallel orsubstantially to the top surface of the dressing. The fluidic connector160 may be adhered and sealed to the backing layer 220 using an adhesivesuch as an acrylic, cyanoacrylate, epoxy, UV curable or hot meltadhesive. The fluidic connector 160 may be formed from a soft polymer,for example a polyethylene, a polyvinyl chloride, a silicone orpolyurethane having a hardness of 30 to 90 on the Shore A scale. In someembodiments, the fluidic connector 160 may be made from a soft orconformable material.

In some embodiments, the absorbent layer 221 includes at least onethrough hole 228 located so as to underlie the fluidic connector 160.The through hole 228 may in some embodiments be the same size as theopening 227 in the backing layer, or may be bigger or smaller. Asillustrated in FIG. 2B a single through hole can be used to produce anopening underlying the fluidic connector 160. It will be appreciatedthat multiple openings could alternatively be utilized. Additionallyshould more than one port be utilized according to certain embodimentsof the present disclosure one or multiple openings may be made in theabsorbent layer and the obscuring layer in registration with eachrespective fluidic connector. Although not essential to certainembodiments of the present disclosure the use of through holes in thesuper-absorbent layer may provide a fluid flow pathway which remainsunblocked in particular when the absorbent layer is near saturation.

The aperture or through-hole 228 can be provided in the absorbent layer221 beneath the orifice 227 such that the orifice is connected directlyto the transmission layer 226 as illustrated in FIG. 2B. This allows thenegative pressure applied to the fluidic connector 160 to becommunicated to the transmission layer 226 without passing through theabsorbent layer 221. This ensures that the negative pressure applied tothe wound site is not inhibited by the absorbent layer as it absorbswound exudates. In other embodiments, no aperture may be provided in theabsorbent layer 221, or alternatively a plurality of aperturesunderlying the orifice 227 may be provided. In further alternativeembodiments, additional layers such as another transmission layer or anobscuring layer such as described in International Patent PublicationWO2014020440, the entirety of which is hereby incorporated by reference,may be provided over the absorbent layer 221 and beneath the backinglayer 220.

The backing layer 220 is can be gas impermeable, but moisture vaporpermeable, and can extend across the width of the wound dressing 155.The backing layer 220, which may for example be a polyurethane film (forexample, Elastollan SP9109) having a pressure sensitive adhesive on oneside, is impermeable to gas and this layer thus operates to cover thewound and to seal a wound cavity over which the wound dressing isplaced. In this way an effective chamber is made between the backinglayer 220 and a wound site where a negative pressure can be established.The backing layer 220 can be sealed to the wound contact layer 222 in aborder region around the circumference of the dressing, ensuring that noair is drawn in through the border area, for example via adhesive orwelding techniques. The backing layer 220 protects the wound fromexternal bacterial contamination (bacterial barrier) and allows liquidfrom wound exudates to be transferred through the layer and evaporatedfrom the film outer surface. The backing layer 220 can include twolayers; a polyurethane film and an adhesive pattern spread onto thefilm. The polyurethane film can be moisture vapor permeable and may bemanufactured from a material that has an increased water transmissionrate when wet. In some embodiments the moisture vapor permeability ofthe backing layer increases when the backing layer becomes wet. Themoisture vapor permeability of the wet backing layer may be up to aboutten times more than the moisture vapor permeability of the dry backinglayer.

The absorbent layer 221 may be of a greater area than the transmissionlayer 226, such that the absorbent layer overlaps the edges of thetransmission layer 226, thereby ensuring that the transmission layerdoes not contact the backing layer 220. This provides an outer channelof the absorbent layer 221 that is in direct contact with the woundcontact layer 222, which aids more rapid absorption of exudates to theabsorbent layer. Furthermore, this outer channel ensures that no liquidis able to pool around the circumference of the wound cavity, which mayotherwise seep through the seal around the perimeter of the dressingleading to the formation of leaks. As illustrated in FIG. 2B, theabsorbent layer 221 may define a smaller perimeter than that of thebacking layer 220, such that a boundary or border region is definedbetween the edge of the absorbent layer 221 and the edge of the backinglayer 220.

As shown in FIG. 2B, one embodiment of the wound dressing 155 comprisesan aperture 228 in the absorbent layer 221 situated underneath thefluidic connector 160. In use, for example when negative pressure isapplied to the dressing 155, a wound facing portion of the fluidicconnector may thus come into contact with the transmission layer 226,which can thus aid in transmitting negative pressure to the wound siteeven when the absorbent layer 221 is filled with wound fluids. Someembodiments may have the backing layer 220 be at least partly adhered tothe transmission layer 226. In some embodiments, the aperture 228 is atleast 1-2 mm larger than the diameter of the wound facing portion of thefluidic connector 11, or the orifice 227.

For example, in embodiments with a single fluidic connector 160 andthrough hole, it may be preferable for the fluidic connector 160 andthrough hole to be located in an off-center position. Such a locationmay permit the dressing 155 to be positioned onto a patient such thatthe fluidic connector 160 is raised in relation to the remainder of thedressing 155. So positioned, the fluidic connector 160 and the filter214 may be less likely to come into contact with wound fluids that couldprematurely occlude the filter 214 so as to impair the transmission ofnegative pressure to the wound site.

Turning now to the fluidic connector 160, some embodiments include asealing surface 216, a bridge 211 with a proximal end (closer to thenegative pressure source) and a distal end 140, and a filter 214. Thesealing surface 216 can form the applicator that is sealed to the topsurface of the wound dressing. In some embodiments a bottom layer of thefluidic connector 160 may comprise the sealing surface 216. The fluidicconnector 160 may further comprise an upper surface vertically spacedfrom the sealing surface 216, which in some embodiments is defined by aseparate upper layer of the fluidic connector. In other embodiments theupper surface and the lower surface may be formed from the same piece ofmaterial. In some embodiments the sealing surface 216 may comprise atleast one aperture 229 therein to communicate with the wound dressing.In some embodiments the filter 214 may be positioned across the opening229 in the sealing surface, and may span the entire opening 229. Thesealing surface 216 may be configured for sealing the fluidic connectorto the cover layer of the wound dressing, and may comprise an adhesiveor weld. In some embodiments, the sealing surface 216 may be placed overan orifice in the cover layer with optional spacer elements 215configured to create a gap between the filter 214 and the transmissionlayer 226. In other embodiments, the sealing surface 216 may bepositioned over an orifice in the cover layer and an aperture in theabsorbent layer 220, permitting the fluidic connector 160 to provide airflow through the transmission layer 226. In some embodiments, the bridge211 may comprise a first fluid passage 212 in communication with asource of negative pressure, the first fluid passage 212 comprising aporous material, such as a 3D knitted material, which may be the same ordifferent than the porous layer 226 described previously. The bridge 211can be encapsulated by at least one flexible film layer 208, 210 havinga proximal and distal end and configured to surround the first fluidpassage 212, the distal end of the flexible film being connected thesealing surface 216. The filter 214 is configured to substantiallyprevent wound exudate from entering the bridge, and spacer elements 215are configured to prevent the fluidic connector from contacting thetransmission layer 226. These elements will be described in greaterdetail below.

Some embodiments may further comprise an optional second fluid passagepositioned above the first fluid passage 212. For example, someembodiments may provide for an air leak may be disposed at the proximalend of the top layer that is configured to provide an air path into thefirst fluid passage 212 and dressing 155 similar to the suction adapteras described in U.S. Pat. No. 8,801,685, which is incorporated byreference herein in its entirety.

In some embodiment, the fluid passage 212 is constructed from acompliant material that is flexible and that also permits fluid to passthrough it if the spacer is kinked or folded over. Suitable materialsfor the fluid passage 212 include without limitation foams, includingopen-cell foams such as polyethylene or polyurethane foam, meshes, 3Dknitted fabrics, non-woven materials, and fluid channels. In someembodiments, the fluid passage 212 may be constructed from materialssimilar to those described above in relation to the transmission layer226. Advantageously, such materials used in the fluid passage 212 notonly permit greater patient comfort, but may also provide greater kinkresistance, such that the fluid passage 212 is still able to transferfluid from the wound toward the source of negative pressure while beingkinked or bent.

In some embodiments, the fluid passage 212 may be comprised of a wickingfabric, for example a knitted or woven spacer fabric (such as a knittedpolyester 3D fabric, Baltex 7970®, or Gehring 879®) or a nonwovenfabric. These materials selected can be suited to channeling woundexudate away from the wound and for transmitting negative pressure orvented air to the wound site, and may also confer a degree of kinking orocclusion resistance to the fluid passage 212. In some embodiments, thewicking fabric may have a three-dimensional structure, which in somecases may aid in wicking fluid or transmitting negative pressure. Incertain embodiments, including wicking fabrics, these materials remainopen and capable of communicating negative pressure to a wound areaunder the typical pressures used in negative pressure therapy, forexample between −40 to −150 mmHg. In some embodiments, the wickingfabric may comprise several layers of material stacked or layered overeach other, which may in some cases be useful in preventing the fluidpassage 212 from collapsing under the application of negative pressure.In other embodiments, the wicking fabric used in the fluid passage 212may be between 1.5 mm and 6 mm; more preferably, the wicking fabric maybe between 3 mm and 6 mm thick, and may be comprised of either one orseveral individual layers of wicking fabric. In other embodiments, thefluid passage 212 may be between 1.2-3 mm thick, and preferably thickerthan 1.5 mm. Some embodiments, for example a suction adapter used with adressing which retains liquid such as wound exudate, may employhydrophobic layers in the fluid passage 212, and only gases may travelthrough the fluid passage 212. Additionally, and as describedpreviously, the materials used in the system can be conformable andsoft, which may help to avoid pressure ulcers and other complicationswhich may result from a wound treatment system being pressed against theskin of a patient.

In some embodiments, the filter element 214 is impermeable to liquids,but permeable to gases, and is provided to act as a liquid barrier andto ensure that no liquids are able to escape from the wound dressing155. The filter element 214 may also function as a bacterial barrier.Typically the pore size is 0.2 μm. Suitable materials for the filtermaterial of the filter element 214 include 0.2 micron Gore™ expandedPTFE from the MMT range, PALL Versapore™ 200R, and Donaldson™ TX6628.Larger pore sizes can also be used but these may require a secondaryfilter layer to ensure full bioburden containment. As wound fluidcontains lipids it is preferable, though not essential, to use anoleophobic filter membrane for example 1.0 micron MMT-332 prior to 0.2micron MMT-323. This prevents the lipids from blocking the hydrophobicfilter. The filter element can be attached or sealed to the port or thecover film over the orifice. For example, the filter element 214 may bemolded into the fluidic connector 160, or may be adhered to one or bothof the top of the cover layer and bottom of the suction adapter 160using an adhesive such as, but not limited to, a UV cured adhesive.

It will be understood that other types of material could be used for thefilter element 214. More generally a microporous membrane can be usedwhich is a thin, flat sheet of polymeric material, this containsbillions of microscopic pores. Depending upon the membrane chosen thesepores can range in size from 0.01 to more than 10 micrometers.Microporous membranes are available in both hydrophilic (waterfiltering) and hydrophobic (water repellent) forms. In some embodiments,filter element 214 comprises a support layer and an acrylic copolymermembrane formed on the support layer. In some embodiments, the wounddressing 155 according to certain embodiments uses microporoushydrophobic membranes (MHMs). Numerous polymers may be employed to formMHMs. For example, the MHMs may be formed from one or more of PTFE,polypropylene, PVDF and acrylic copolymer. All of these optionalpolymers can be treated in order to obtain specific surfacecharacteristics that can be both hydrophobic and oleophobic. As suchthese will repel liquids with low surface tensions such as multi-vitamininfusions, lipids, surfactants, oils and organic solvents.

MHMs block liquids whilst allowing air to flow through the membranes.They are also highly efficient air filters eliminating potentiallyinfectious aerosols and particles. A single piece of MHM is well knownas an option to replace mechanical valves or vents. Incorporation ofMHMs can thus reduce product assembly costs improving profits andcosts/benefit ratio to a patient.

The filter element 214 may also include an odor absorbent material, forexample activated charcoal, carbon fiber cloth or Vitec Carbotec-RTQ2003073 foam, or the like. For example, an odor absorbent material mayform a layer of the filter element 214 or may be sandwiched betweenmicroporous hydrophobic membranes within the filter element. The filterelement 214 thus enables gas to be exhausted through the orifice.Liquid, particulates and pathogens however are contained in thedressing.

The wound dressing 155 may comprise spacer elements 215 in conjunctionwith the fluidic connector 160 and the filter 214. With the addition ofsuch spacer elements 215 the fluidic connector 160 and filter 214 may besupported out of direct contact with the absorbent layer 220 or thetransmission layer 226. The absorbent layer 220 may also act as anadditional spacer element to keep the filter 214 from contacting thetransmission layer 226. Accordingly, with such a configuration contactof the filter 214 with the transmission layer 226 and wound fluidsduring use may thus be minimized.

Similar to the embodiments of wound dressings described herein, somewound dressings comprise a perforated wound contact layer, which caninclude silicone adhesive on the wound- or skin-contact face and/oracrylic adhesive on the reverse. The wound contact layer can beperforated to match any pattern suitable of a particular wound. Abovethis bordered layer sits a transmission layer or a 3D spacer fabric pad.Above the transmission layer, sits an absorbent layer. The absorbentlayer can include a superabsorbent non-woven (NW) pad. The absorbentlayer can over-border the transmission layer by approximately 5 mm atthe perimeter. The absorbent layer can have an aperture or through-holetoward one end. The aperture can be about 10 mm in diameter. Over thetransmission layer and absorbent layer lies a backing layer. The backinglayer can be a high moisture vapor transmission rate (MVTR) film,pattern coated with acrylic adhesive. The high MVTR film and woundcontact layer encapsulate the transmission layer and absorbent layer,creating a perimeter border of approximately 20 mm. The backing layercan have a 10 mm aperture that overlies the aperture in the absorbentlayer. Above the hole can be bonded a fluidic connector that comprises aliquid-impermeable, gas-permeable semi-permeable membrane (SPM) orfilter that overlies the aforementioned apertures.

Wound Dressing with Sensors

As described herein, a wound dressing that incorporates a number ofsensors can be utilized in order to monitor characteristics of a woundas it heals. Collecting data from the wounds that heal well, and fromthose that do not, can provide useful insights towards identifyingmeasurands to indicate one or more of whether a wound is on a healing ornon-healing trajectory, provide wound status, clinical feedback, or thelike. Any of the disclosed wound dressings, such as wound dressing 22can include one or more of the following features or any other featuresdisclosed herein.

In some implementations, a number of sensor technologies can be used inwound dressings or one or more components forming part of an overallwound dressing apparatus. For example, as illustrated in FIGS. 3 and 4D,which depict wound dressings 250 and 320 with sensor arrays according tosome embodiments, one or more sensors can be incorporated onto or into awound contact layer, which may be a perforated wound contact layer asshown in FIG. 4D. The wound contact layer in FIGS. 3 and 4D isillustrated as having a square shape, but it will be appreciated thatthe wound contact layer may have other shapes such as rectangular,circular, oval, etc. In some embodiments, the sensor integrated woundcontact layer can be provided as an individual material layer that isplaced over the wound area and then covered by a wound dressingapparatus or components of a wound dressing apparatus, such as gauze,foam or other wound packing material, a superabsorbent layer, a drape, afully integrated dressing like the Pico or Allevyn Life dressing, etc.In other embodiments, the sensor integrated wound contact layer may bepart of a single unit dressing such as described herein.

The sensor-integrated wound contact layer can be placed in contact withthe wound and will allow fluid to pass through the contact layer whilecausing little to no damage to the tissue in the wound. Thesensor-integrated wound contact layer can be made of a flexible materialsuch as silicone and can incorporate antimicrobials or other therapeuticagents known in the art. In some embodiments, the sensor-integratedwound contact layer can incorporate adhesives that adhere to wet or drytissue. In some embodiments, the sensors or sensor array can beincorporated into or encapsulated within other components of the wounddressing such as the absorbent layer or spacer layer described above.

As shown in FIGS. 3 and 4D, five sensors can be used, including, forinstance, sensors for temperature (such as, 25 thermistor sensors, in a5×5 array, ˜20 mm pitch), oxygen saturation or SpO2 (such as, 4 or 5SpO2 sensors, in a single line from the center of the wound contactlayer to the edge thereof, 10 mm pitch), tissue color (such as, 10optical sensors, in 2×5 array, ˜20 mm pitch; not all 5 sensors in eachrow of the array need be aligned), pH (such as, by measuring colour of apH sensitive pad, optionally using the same optical sensors as fortissue colour), and conductivity (such as, 9 conductivity contacts, in a3×3 array, ˜40 mm pitch). As shown in FIG. 4A, the SpO2 sensors can bearranged in a single line from the center of or near the center of thewound contact layer to the edge of the wound contact layer. The line ofSpO2 sensors can allow the sensor to take measurements in the middle ofthe wound, at the edge or the wound, or on intact skin to measurechanges between the various regions. In some embodiments, the woundcontact layer or sensor array can be larger than the size of the woundto cover the entire surface area of the wound as well as the surroundingintact skin. The larger size of the wound contact layer and/or sensorarray and the multiple sensors can provide more information about thewound area than if the sensor was only placed in the center of the woundor in only one area at a time.

The sensors can be incorporated onto flexible circuit boards formed offlexible polymers including polyamide, polyimide (PI), polyester,polyethylene naphthalate (PEN), polyetherimide (PEI), along with variousfluoropolymers (FEP) and copolymers, or any material known in the art.The sensor array can be incorporated into a two-layer flexible circuit.In some embodiments, the circuit board can be a multi-layer flexiblecircuit board. In some embodiments, these flexible circuits can beincorporated into any layer of the wound dressing. In some embodiments,a flexible circuit can be incorporated into a wound contact layer. Forexample, the flexible circuit can be incorporated into a wound contactlayer similar to the wound contact layer described with reference toFIG. 2B. The wound contact layer can have cutouts or slits that allowfor one or more sensors to protrude out of the lower surface of thewound contact layer and contact the wound area directly.

In some embodiments, the sensor-integrated wound contact layer caninclude a first and second wound contact layer with the flexible circuitboard sandwiched between the two layers of wound contact layer material.The first wound contact layer has a lower surface intended to be incontact with the wound and an upper surface intended to be in contactwith flexible circuit board. The second wound contact layer has a lowersurface intended to be in contact with the flexible circuit board and anupper surface intended to be in contact with a wound dressings or one ormore components forming part of an overall wound dressing apparatus. Theupper surface of the first wound contact layer and the lower surface ofthe second wound contact layer can be adhered together with the flexiblecircuit board sandwiched between the two layers.

In some embodiments, the one or more sensors of the flexible circuitboard can be fully encapsulated or covered by the wound contact layersto prevent contact with moisture or fluid in the wound. In someembodiments, the first wound contact layer can have cutouts or slitsthat allow for one or more sensors to protrude out of the lower surfaceand contact the wound area directly. For example, the one or more SpO2sensors as shown in FIG. 4D are shown protruding out the bottom surfaceof the wound contact layer. In some embodiments, the SpO2 sensors can bemounted directly on a lower surface of the first wound contact layer.Some or all of the sensors and electrical or electronic components maybe potted or encapsulated (for example, rendered waterproof orliquid-proof) with a polymer, for example, silicone or epoxy basedpolymers. The encapsulation with a polymer can prevent ingress of fluidand leaching of chemicals from the components. In some embodiments, thewound contact layer material can seal the components from water ingressand leaching of chemicals.

In some embodiments, gathering and processing information related to thewound can utilize three components, including a sensor array, a controlor processing module, and software. These components are described inmore detail herein.

FIG. 4A illustrates a flexible sensor array circuit board 300 thatincludes a sensor array portion 301, a tail portion 302, and a connectorpad end portion 303 according to some embodiments. The sensor arrayportion 301 can include the sensors and associated circuitry. The sensorarray circuit board 300 can include a long tail portion 302 extendingfrom the sensor array portion 301. The connector pad end portion 303 canbe enabled to connect to a control module or other processing unit toreceive the data from the sensor array circuit. The long tail portion302 can allow the control module to be placed distant from the wound,such as for example in a more convenient location away from the wound.

FIG. 4B illustrates embodiments of the flexible circuit boards with fourdifferent sensor array geometries 301A, 301B, 301C, and 301D accordingto some embodiments. The illustrated embodiments include tail portions302A, 302B. 302C, and 302D. In some embodiments, flexible circuit boardsinclude a short portion or no tail portion. In some embodiments, fourdifferent sensor array geometries shown can be implemented in flexiblecircuits. While FIG. 4B show four different sensor array formats andconfigurations, the design 301B and 302B also includes the connectorpads end portion 303 configured to provide electrical or electronicconnection between the sponsor array 301B and a control module. One ormore of the designs in 301A, 301C, or 301D can also include a connectorpads end portion, such as the portion 303, to allow flexible circuitboards 301A, 301C, or 301D to communicate with a control module or otherprocessing unit. In some embodiments, the sensor array communicates withthe control module wirelessly and the tail portion may be omitted.

FIG. 4C shows the sensor array portion 301B of the sensor array designof FIG. 4B in more detail. In any one or more of the embodiments of FIG.3 or 4A-4D, the sensor array portion can include a plurality of portionsthat extend either around a perimeter of a wound dressing component suchas a wound contact layer, or inward from an outer edge of the wounddressing component. For example, the illustrated embodiments include aplurality of linearly extending portions that may be parallel to edgesof a wound dressing component, and in some embodiments, follow theentire perimeter of the wound dressing component. In some embodiments,the sensor array portion may comprise a first plurality of parallellinearly extending portions that are perpendicular to a second pluralityof parallel linearly extending portions. These linearly extendingportions may also have different lengths and may extend inward todifferent locations within an interior of a wound dressing component.The sensor array portion preferably does not cover the entire wounddressing component, so that gaps are formed between portions of thesensor array. As shown in FIG. 3 , this allows some, and possibly amajority of the wound dressing component to be uncovered by the sensorarray. For example, for a perforated wound contact layer as shown inFIGS. 3 and 4D, the sensor array portion 301 may not block a majority ofthe perforations in the wound contact layer. In some embodiments, thesensor array may also be perforated or shaped to match the perforationsin the wound contact layer to minimize the blocking of perforations tofluid flow.

FIG. 4D illustrates a flexible sensor array incorporated into aperforated wound contact layer 320 according to some embodiments. As isillustrated, the sensor array can be sandwiched between two films orwound contact layers. The wound contact layers can have perforationsformed as slits or holes as described herein that are small enough tohelp prevent tissue ingrowth into the wound dressing while allowingwound exudate to flow into the dressing. In some embodiments, the woundcontact layers can have one or more slits that increase flexibility ofthe wound contact layer with integrated sensor array. In someembodiments, one of the wound contact layers can have extra cut outs toaccommodate the sensors so that they can contact the skin directly.

Connectivity for the sensor array can vary depending on the varioussensors and sensor array designs utilized. In some embodiments, forexample as shown in FIG. 4B, a total of 79 connections can be used toconnect the components of the sensor array. The sensor arrays can beterminated in two parallel 40-way 0.5 mm pitch Flat Flexible Cable (FFC)contact surfaces, with terminals on the top surface, designed to beconnected to an FFC connector such as Molex 54104-4031.

In some embodiments, one or more of sensors, such as thermistors,conductivity sensors, SpO2 sensors, color sensors, or the like, can beused on the sensor array to provide information relating to conditionsof the wound and/or periwound. Any of the sensor arrays and/orindividual sensors disclosed herein can assist a clinician in monitoringthe status of the wound, which can include healing of the wound ornon-healing of the wound (such as, static, degrading, or the like). Theone or more sensors can operate individually or in coordination witheach other to provide data relating to the wound and wound healingcharacteristics.

Temperature sensors can use thermocouples or thermistors to measuretemperature. The thermistors can be used to measure or track thetemperature of the underlying wound or the thermal environment withinthe wound dressing. The thermometry sensors can be calibrated and thedata obtained from the sensors can be processed to provide informationabout the wound environment. In some embodiments, an ambient sensormeasuring ambient air temperature can also be used to assist ineliminating problems associated with environment temperature shifts.

Optical sensors can be used to measure wound appearance using an RGBsensor with an illumination source. In some embodiments, both the RGBsensor and the illumination source would be pressed up against the skin,such that light would penetrate into the tissue and take on the spectralfeatures of the tissue itself.

Light propagation in tissue can be dominated by two major phenomena,scattering and attenuation. For attenuation, as light passes throughtissue, its intensity may be lost due to absorption by variouscomponents of the tissue. Blue light tends to be attenuated heavily,whilst light at the red end of the spectrum tends to be attenuatedleast.

Scattering processes can be more complex, and can have various “regimes”which must be considered. The first aspect of scattering is based on thesize of the scattering centre compared with the wavelength of incidentlight. If the scattering center is much smaller than the wavelength oflight, then Rayleigh scattering can be assumed. If the scattering centeris on the order of the wavelength of light, then a more detailed Miescattering formulation must be considered. Another factor involved inscattering light is the distance between input and output of thescattering media. If the mean free path of the light (the distancebetween scattering events) is much larger than the distance traveled,then ballistic photon transport is assumed. In the case of tissue,scatting events are approximately 100 microns apart—so a 1 mm pathdistance would effectively randomise the photon direction and the systemwould enter a diffusive regime.

Ultra bright light emitting diodes (LEDs), an RGB sensor, and polyesteroptical filters can be used as components of the optical sensors tomeasure through tissue color differentiation. For example, becausesurface color can be measured from reflected light, a color can bemeasured from light which has passed through the tissue first for agiven geometry. This can include color sensing from diffuse scatteredlight, from an LED in contact with the skin. In some embodiments, an LEDcan be used with an RGB sensor nearby to detect the light which hasdiffused through the tissue. The optical sensors can image with diffuseinternal light or surface reflected light.

Additionally, the optical sensors can be used to measureautofluorescence. Autoflourescense is used because the tissue isabsorbing light at one wavelength, and emitting at another.Additionally, dead tissue may not auto-fluoresce and so this could be avery strong indication as to if the tissue is healthy or not. Due toblue light (or even UV light) having such a short penetration depth, itmay be very useful for example to have a UV light with a red sensitivephotodiode nearby (or some other wavelength shifted band) to act as abinary test for healthy tissue, which would auto-fluoresce at a veryparticular wavelength.

Conductivity sensors can be used to determine the difference betweenliving and dead tissue or to show a change in impedance due to a woundbeing opened up in morbid tissue. Conductivity sensors can includeAg/AgCl electrodes and an impedance analyser. The conductivity sensorscan be used to measure the change of impedance of a region of woundgrowth by measuring the impedance of the surrounding tissue/area. Insome embodiments, the sensor array can utilize conductivity sensors tomeasure the change in conductivity on perimeter electrodes due to awound size or wound shape change. In some embodiments, the conductivitysensors can be used in the wound bed or on the perimeter of the wound.

In some embodiments, pH changing pads can be used as a pH sensor. Aspectrometer and a broadband white light source can be used to measurethe spectral response of the pH dye. The illumination and imaging can beprovided on the surface of the wound dressing that is in contact withthe wound and at the same side as the fluid application, the bottomsurface. Alternatively, in some embodiments, the illumination andimaging source can be provided on the surface of the wound dressingopposite the bottom surface and away from fluid application or the topsurface of the dressing.

In some embodiments, pulse oximetry SpO2 sensors can be used. To measurehow oxygenated the blood is and the pulsatile blood flow can beobserved. Pulse oximetry measurements work by taking a time resolvedmeasurement of light absorption/transmission in tissue at two differentoptical wavelengths. When hemoglobin becomes oxygenated, its absorptionspectrum changes with regards to non-oxygenated blood. By taking ameasurement at two different wavelengths, one gains a ratio metricmeasure of how oxygenated the blood is.

The components in the sensor array can be connected through multipleconnections. In some embodiments, the thermistors can be arranged ingroups of five. Each thermistor is nominally 10 kΩ, and each group offive has a common ground. There are five groups of thermistors, giving atotal of 30 connections. In some embodiments, there can be nineconductivity terminals. Each conductivity terminal requires oneconnection, giving a total of 9 connections. In some embodiments, therecan be five SpO2 sensors. Each SpO2 sensor requires three connections,plus power and ground (these are covered separately), giving a total of15 connections. In some embodiments, there can be 10 color sensors. Eachcolor sensor comprises an RGB LED and an RGB photodiode. Each colorsensor requires six connections, however five of these are common toevery sensor, giving a total of 15 connections. Power and ground areconsidered separately. In some embodiments, there can be 5 pH sensors.The pH sensors can be a color-change discs, and can be sensed using thecolor sensors described above. Therefore, the pH sensors require noadditional connections. There can be three power rails, and seven groundreturn signals, giving a total of 10 common connections. In someembodiments, the sensor array can include 25 thermistor (MurataNCP15WB473E03RC), 9 conductivity terminal, 5 SpO2 (ADPD144RI), 10 RGBLED (such as KPTF-1616RGBC-13), 10 RGB Color Sensor, 10 FET, a printedcircuit board (PCB), and an assembly.

As described herein, a control module can be used to interface with thesensor array. Controller 24 can include one or more of the followingfeatures. In some embodiments, the control module can contain a powersource, such as batteries, and electronics to drive the sensors. Thecontrol module can also log data at appropriate intervals and allow datatransfer to an external computing device, such as a personal computer(PC) as shown in FIG. 1A. The control module can be customized to havevarious features depending on the sensors used in the sensor array andthe data collected by the sensors. In some embodiments, the controlmodule can be comfortable enough and small enough to be worncontinuously for several weeks. In some embodiments, the control modulecan be positioned near the wound dressing or on the wound dressing. Insome embodiments, the control module can be positioned in a remotelocation from the wound dressing and accompanying sensor array. Thecontrol module can communicate with the sensor array and wound dressingthrough electrical wires or through wireless communication whetherpositioned on the dressing, near the dressing, or remote from the wounddressing. In some embodiments, the control module can be adapted to beutilized with different sensor arrays and can enable easy replacement ofthe sensor array.

In some embodiments, the control module can include various requirementsand combination of features including but not limited to the featureslisted in Table 1 below.

TABLE 1 OPTIONAL FEATURES FOR CONTROL MODULE 7 day operation from asingle set of batteries 28 day local, non-volatile, storage capacityEasy to charge, or to replace battery Wireless link to PC/tablet (suchas Bluetooth) Wired link to PC (optional, micro-USB) Drive electronicsfor thermistors Drive electronics for conductivity sensors Driveelectronics for optical sensors Drive electronics for SpO2 sensors Powermanagement Real Time Clock (RTC) to allow accurate data logging, andcorrelation with other measurands Ability to change sample rates andintervals (useful for SpO2) for each sensor Indication of status viaLED, such as (Green: Awake; Flashing green: Charging; Blue: Wirelesslink established; Flashing blue: Wireless data transfer; Yellow: Wiredlink established; Flashing yellow: Wired data transfer; Red: Batterylow; Flashing red: Battery very low

FIG. 4E illustrates a block diagram 330 of a control module according tosome embodiments. Controller 24 can include one or more of theillustrated and described features. The block diagram of the controlmodule includes a conductivity driver box 391 displaying features of theconductivity driver. Box 392 shows the features of the thermistorinterface and box 393 shows the features of the optical interface. Thecontrol module can include a controller or microprocessor with featuressimilar to those shown in box 394. Real time clock (RTC), Status LEDs,USB connector, Serial Flash, and Debug Connector can be included asfeatures of the control module as shown in FIG. 4E.

In some embodiments, the microprocessor can have one or more of thefollowing features: 2.4 GHz or another suitable frequency radio 395(either integrated, or external) with a suitable antenna or antennas;Supplied Bluetooth software stack; SPI interface; USB (or UART forexternal USB driver); I2C; 3 channel PWM; 32 GPIO; or 6-channel ADC. Insome embodiments, the device can require at least 48 I/O pins orpossibly more due to banking limitations. Bluetooth stack typicallyrequires ˜20 kB on-board Flash, so a minimum of 32 kB can be required.In some embodiment, 64 kB can be required if complex data processing isconsidered. The processor core can be ARM Cortex M4 or a similarprocessor core. In some embodiments, the parts can include ST'sSTM32L433LC or STM32F302R8, which would require an external radio, orNXP's Kinetis KW range including integrated radio.

In some embodiment, the control module can include a memory componentwhere the amount of local storage depends on the sample rate andresolution of the sensors. For example, an estimated data requirement of256 Mb (32 MB) can be met by using a serial Flash device from a numberof manufacturers (Micron, Spansion).

The control module can utilize one or more analogue switches. In someembodiments, analogue switches with good on resistance and reasonablebandwidth can be used. For example, Analog Devices' ADG72 or NXP'sNX3L4051HR can be used. Based on the initial system architecture, 8 ofthese will be required.

The control module can incorporate a power source, such as a battery.For example a 300 mWh/day battery can be used. For 7 days this is 2100mWh. This could be provided by: a 10 days, non-rechargeable, ER14250(14.5 mm diameter×25 mm) LiSOCl2 cell; or a 7 days, rechargeable, Li14500 (14.5 mm diameter×500 mm) Li-Ion.

The control module can incorporate a real time clock (RTC). The RTC canbe chosen from any RTC devices with crystal. The control module can alsoinclude miscellaneous resistors, capacitors, connectors, chargecontrollers, and other power supplies.

The PCB of the control module can be a 4-layer board, approximately 50mm×20 mm, or 25 mm×40 mm. The type of PCB used can be largely driven byconnection requirements to sensor array.

The enclosure of the control module can be a two part moulding, withclip features to allow easy access for changing sensor arrays orbatteries.

The data collected through the sensor array can be passed through thecontrol module and processed by host software. The software may beexecuted on a computing or processing device (see FIG. 1A). Theprocessing device can be a PC, tablet, smartphone, or other computercapable of running host software. The processing device executing thesoftware can be in communication with the control module throughelectrical wires or through wireless communication. In some embodiments,the software may be configured to provide access to the data held on thecontrol module, but not to perform big-data analysis. The host softwarecan include an interface to the control module via Bluetooth or USB. Insome embodiments, the host software can read the status of controlmodule, download logged data from control module, upload sample ratecontrol to control module, convert data from control module into formatsuitable for processing by big-data analysis engine, or upload data tocloud (see FIG. 1A) for processing by analysis engine.

The software may be developed for PC (Windows/Linux), tablet orsmartphone (Android/iOS), or for multiple platforms.

Additional embodiments of wound dressing with sensors and other relatedsystems are disclosed in International Application No.PCT/IB2017/000693, filed on May 12, 2017, titled SENSOR ENABLED WOUNDMONITORING AND THERAPY APPARATUS, the disclosure of which is herebyincorporated by reference in its entirety.

In some embodiments, a source of negative pressure (such as a pump) andsome or all other components of the topical negative pressure system,such as power source(s), sensor(s), connector(s), user interfacecomponent(s) (such as button(s), switch(es), speaker(s), screen(s),etc.) and the like, can be integral with the wound dressing. In someembodiments, the components can be integrated below, within, on top of,or adjacent to the backing layer. In some embodiments, the wounddressing can include a second cover layer or a second filter layer forpositioning over the layers of the wound dressing and any of theintegrated components. The second cover layer can be the upper mostlayer of the dressing or can be a separate envelope that enclosed theintegrated components of the topical negative pressure system.

As used herein the upper layer, top layer, or layer above refers to alayer furthest from the surface of the skin or wound while the dressingis in use and positioned over the wound. Accordingly, the lower surface,lower layer, bottom layer, or layer below refers to the layer that isclosest to the surface of the skin or wound while the dressing is in useand positioned over the wound.

Component Positioning in Sensor Enabled Wound Dressing

In some embodiments, electrical or electronic components, such assensors, connections, or the like, can be placed or positioned on orembedded in one or more wound dressing components, which can be placedin or on the wound, skin, or both the wound and the skin. For example,one or more electronic components can be positioned on a wound contactlayer side that faces the wound, such as the lower surface 224 of thewound contact layer 222 in FIG. 2B. The wound contact layer can beflexible, elastic, or stretchable or substantially flexible, elastic, orstretchable in order to conform to or cover the wound. For example, thewound contact layer can be made from a stretchable or substantiallystretchable material, such as one or more of polyurethane, thermoplasticpolyurethane (TPU), silicone, polycarbonate, polyethylene, polyimide,polyamide, polyester, polyethelene tetraphthalate (PET), polybutalenetetreaphthalate (PBT), polyethylene naphthalate (PEN), polyetherimide(PEI), along with various fluropolymers (FEP) and copolymers, or anothersuitable material. In some instances, one or more electronic componentscan be alternatively or additionally placed or positioned on or embeddedin any one or more of a transmission layer, absorbent layer, backinglayer, or any other suitable layer of the wound dressing.

Stretchable or substantially stretchable material can be stretched to 5%or less or more, 10% or less or more, 20% or less or more, or more than20% of its starting dimensions, such as length or width. In some cases,the stretchable or substantially stretchable material can return towithin 5% or less or more of the starting dimensions (such as length orwidth) after being stretched.

In some implementations, while it may be desirable for the wound contactlayer to be stretchable to better conform to or cover the wound, atleast some of the electronic components may not be stretchable orflexible. In such instances, undesirable or excessive localized strainor stress may be exerted on the one or more electronic components, suchas on the supporting area or mountings of an electronic component, whenthe wound is dressed with the wound dressing and the wound contact layeris positioned in or over the wound. For example, such stress can be dueto patient movement, changes in the shape or size of the wound (such as,due to its healing), or the like. Such stress may cause movement,dislodgment, or malfunction of the one or more electronic components(for example, creation of an open circuit from a pin or anotherconnector becoming disconnected).

Alternatively or additionally, it may be desirable to maintain theposition of one or more electronic components, such as one or moresensors, in the same or substantially same location or region on thewound contact layer with respect to the wound (such as, in contact withthe wound) so that measurements collected by the one or more electroniccomponents accurately capture changes over time in the same orsubstantially same location or region of the wound. While the surface ofthe stretchable wound contact layer may move when, for example, thepatient moves, it may be desirable to have the one or more electroniccomponents be located in the same location or region with respect to thewound.

As described herein, in some embodiments, one or more stiff, rigid, ornon-stretchable or substantially stiff, rigid, or non-stretchableregions, such as one or more regions of non-stretchable or substantiallynon-stretchable material, can be mounted, positioned, or placed on thewound contact layer (or another suitable wound dressing component) forsupporting one or more electronic components. Mounting, positioning, orplacing one or more electronic components in the one or morenon-stretchable or substantially non-stretchable regions can preventformation of localized stress or assist with maintenance of the positionof the one or more electronic components with respect to the wound. Insome instances, one or more electronic components can be alternativelyor additionally be flexible, such as mounted or printed on or supportedby one or more flexible materials. For example, flexible plastic sheetsor substrates, such as polyimide, polyether ether ketone (PEEK),polyester, silicone, or the like, can be used.

FIGS. 5A-5B illustrate a wound dressing 400 with a plurality ofelectronic components according to some embodiments. As is shown, asheet or substrate 430 is configured to support one or more electroniccomponents, including an electronic component or module 402 with aplurality of connectors 404 and a plurality of electronic connections410, and non-stretchable or substantially non-stretchable regions 422and 424. The substrate 430 can be a stretchable or substantiallystretchable wound contact layer as described herein. The electronicmodule 402 can be any electronic component described herein, such as asensor, light source (such as an LED, temperature sensor, opticalsensor, etc.), controller or processor (such as a communicationprocessor), or the like. Electronic connections 410 can be tracksprinted on the substrate 430, such as using conductive copper,conductive ink (such as silver ink, silver/silver chloride ink, copperink, graphite ink, carbon ink, dielectric ink, etc.), or the like. Atleast some of the electronic connections 410 can be flexible orstretchable or substantially flexible or stretchable. Connectors 404 canbe configured to electronically connect the electronic module 402 to theelectronic connection 410 (as illustrated in FIG. 4B), which in turn canbe connected to other electronic modules (not shown) positioned on thesubstrate 430, on or in other components of the wound dressing, orexternal to the wound dressing. Connectors 404 can be pins, leads,bumps, or the like. Additionally or alternatively a socket can be usedto support and electronically connect the electronic module 402. Regions422 and 424 can include non-stretchable or substantially non-stretchablematerial, such as one or more of suitable adhesive, epoxy, polyester,polyimide, polyamide, PET, PBT, or another type of material with a highYoung's modulus. One or more of the regions 422 and 424 can be printedon the substrate 430. As is used herein, printing material on asubstrate can include one or more of laminating, adhering, or any othersuitable technique.

FIG. 5B illustrates components positioned on the substrate 430. Asshown, the electronic module 402 is mounted to or supported by theregion 422. A portion or part of the electronic connections 410 ismounted to or supported by the region 424. Also illustrated are slits,holes, or perforations formed in the substrate 430 according to someembodiments. As described herein, the substrate 430 can be perforatedusing one or more of a cold pin perforation, hot pin perforation, laserablation perforation, ultrasonic or ultrasound perforation, or the liketo make the wound contact layer permeable to liquid and gas. In someimplementations, one or more utilized perforation processes can generateeither a flat or substantially substrate around the hole or an unevensurface (such as donut-shaped surface). Having a flat or substantiallyflat substrate can assist in generating a homogenous layer whenconformal coating is applied (such as, via spray, brush, extrusion dye,or the like as described herein). Further, using a perforation processthat leaves the surface of the substrate uneven or substantially unevencan introduce a greater risk of dislodging one or more components, suchas the electronic connections 410 or the electronic module 402 whenperforations are made around the components.

In certain implementations, perforations are made or patterned aroundone or more components placed on the substrate 430, such as theelectronic connections 410, the electronic module 402, or the regions422 or 424. Component indexing can be used to automatically locateposition of the one or more components on the substrate 430 so that theone or more components are not damaged by perforations. In someembodiments, the substrate can be perforated before one or morecomponents illustrated in FIG. 4A as placed on the substrate.

In some embodiments, in addition to or instead of the one of moreregions 422 or 424, electronic components supported by the substrate 430can be coated with non-stretchable or substantially non-stretchablecoating (not shown), particularly if the substrate 430 is stretchable orsubstantially stretchable. As described herein, such coating can providestress relief for the electronic components (which may includeelectronic modules or electronic connections). Coating can be applied onand around the electronic components. Coating can be one or more ofbiocompatible or hydrophobic.

Any non-stretchable or substantially non-stretchable coating describedherein can be formed from acrylated or modified urethane material (suchas, Henkel Loctite 3211). For example, coating can be one or more ofDymax 1901-M, Dymax 9001-E, Dymax 20351, Dymax 20558, Henkel Loctite3211, or another suitable material.

In some embodiments, conformal coating (not shown) configured toencapsulate or coat one or more of the substrate 430 or componentssupported by the substrate, such as the electronic connections 410 orthe electronic module 402 can be applied. Such coating can providebiocompatibility, shield or protect the electronics from coming intocontact with fluids, or the like. Coating can include one or moresuitable polymers, adhesives, such as 1072-M adhesive (for example Dymax1072-M), 1165-M adhesive (such as, NovaChem Optimax 8002-LV, Dymax1165-M, or the like), 10901-M adhesive (for instance, Dymax 1901-M or9001-E Dymax), parylene (such as, Parylene C), silicones, epoxies,urethanes, acrylated urethanes, acrylated urethane alternatives (suchas, Henkel Loctite 3381), or other suitable biocompatible andsubstantially stretchable materials. Conformal coating can be applied tothe other side of the substrate 430 (such as, the side that does notsupport components) to encapsulate the substrate 430 in conformalcoating.

Additional details regarding one or more of the wound dressing 400,non-stretchable or substantially non-stretchable coating, or conformalcoating are described in one or more of International Patent ApplicationNo. PCT/EP2018/059333, filed on 11 Apr. 2018, or International PatentApplication No. PCT/EP2018/069883, filed on 23 Jul. 2018, each of whichis incorporated by reference in its entirety.

In some embodiments, one or more sensors can be positioned in or on alayer or layers of a wound dressing or another structure that is not indirect contact with a wound. In such cases, the sensors can measure oneor more of impedance, temperature, color, pressure, or the likeassociated with the wound and/or periwound. For example, one or moresensors can be positioned above a dressing layer that transports orabsorbs wound exudate. In this example, the one or more sensors canmeasure one or more of impedance, temperature, color, or the like of thewound exudate. These measurements can be used to determine status of thewound, which (as described herein) can include healing of the wound ornon-healing of the wound.

Other Variations

In some embodiments, a wound monitoring and/or therapy system includes awound dressing comprising one or more sensors configured to obtainmeasurement data of at least one of a wound or periwound. The system canalso include one or more of the following: a controller configured to beconnected to the wound dressing and further configured to receivemeasurement data from the wound dressing, a communication deviceconfigured to be connected to the controller and further configured toperiodically receive data from the controller, a skin perfusionmeasurement device configured to measure skin perfusion pressure in atarget area of the patient, a computing device configured to beconnected to the communication device and the perfusion measurementdevice, the computing device further configured to receive data from thecommunication device and the perfusion measurement device, and a remotecomputing device configured to receive and aggregate data from thecomputing device.

The system of preceding paragraph can include one or more of thefollowing features. The system can include a computing device configuredto take one or more images of at least one of the wound or periwound andcommunicate image data to the remote computing device. The wounddressing can include a substantially flexible wound contact layersupporting the one or more sensors. The wound dressing can also includean antenna configured to communicate measurement data to at least one ofthe controller or communication device.

In some embodiments, a wound monitoring apparatus includes a wounddressing configured to be positioned in contact with a wound, the wounddressing including at least one substantially flexible substratesupporting one or more sensors.

The system and/or apparatus of one or more preceding paragraphs caninclude one or more of the following features. The at least onesubstantially flexible substrate can include a substantially flexibleprinted circuit. The substantially flexible printed circuit can includea flexible polymer. The at least one substantially flexible substratecan include a substantially flexible non-conducting mesh. The mesh caninclude a plurality of perforations. The one or more sensors can includea plurality of sensors electrically connected with each other, theplurality of sensors further configured to be electrically connectedwith a controller and a power source. The one or more sensors caninclude one or more temperature sensors, conductivity sensors,multispectral optical measurements sensors, pH sensors, pressuresensors, colorimetric sensors, optical sensors, ultraviolet (UV)sensors, or infrared (IR) sensors. The system and/or apparatus caninclude a controller in electrical communication with the one or moresensors, the controller configured to receive data from the one or moresensors and communicate the data to a processing device configured toprocess the data collected by the one or more sensors to determine oneor more conditions associated with the wound.

The system and/or apparatus of one or more preceding paragraphs caninclude one or more of the following features. The at least one of thecontroller or the processing device can be configured to indicate, basedon the one or more conditions associated with the wound, that the woundis healing or not healing. The controller can be configured towirelessly communicate with at least one of the one or more sensors orthe processing device. The controller can be configured to be inelectrical communication with at least one of the one or more sensors orthe processing device through one or more conductive tracks. Theprocessing device can include a personal computer (PC), a tablet formatcomputing device, a smartphone, or a custom computing device. Datacollected by the one or more sensors can be configured to becommunicated to a cloud computing device.

The system and/or apparatus of one or more preceding paragraphs caninclude one or more of the following features. The wound dressing caninclude a wound contact layer and the substrate can be positioned on orin the wound contact layer. The wound contact layer can include a firstwound contact layer and a second wound contact layer, wherein thesubstrate is sandwiched between the first and second wound contactlayers. At least one of the one or more sensors can be configured to bein direct contact with the wound and the at least one of the one or moresensors can be encapsulated between the first wound contact layer andthe second wound contact layer. One or more sensors can include at leasta first sensor configured to the in direct contact with the wound and atleast a second sensor configured to not contact the wound.

The system and/or apparatus of one or more preceding paragraphs caninclude one or more of the following features. The system and/orapparatus can include an absorbent layer positioned over the woundcontact layer and a backing layer positioned over the wound contactlayer and the wound contact layer can be sealed to the backing layer.The system and/or apparatus can include a port on the backing layer, theport configured to connect the wound dressing to a source of negativepressure. The wound dressing can be included in a multi-layer wounddressing configured to treat the wound without the use of negativepressure. The system and/or apparatus can include a wound packing layerand a drape that are configured to be positioned over the woundseparately from the wound dressing. The system and/or apparatus caninclude a negative pressure source configured to be in fluidcommunication with the wound dressing and further configured to applynegative pressure to the wound.

In some embodiments, a wound monitoring apparatus includes a wounddressing configured to be positioned in contact with a wound, the wounddressing comprising one or more sensors configured to obtain measurementdata of at least one of the wound or periwound and a controllerconfigured to receive measurement data obtained by the one or moresensors, and transmit measurement data to a remote computing deviceaccording to a security protocol.

The apparatus of the preceding paragraph can include one or more of thefollowing features. The wound dressing can include a substantiallyflexible wound contact layer supporting the one or more sensors. Thesecurity protocol can include encrypting the measurement data. Thesecurity protocol can comprise not including in the transmission patientidentification information or real time clock information associatedwith the measurement data. The controller can be further configured tomaintain non-real time clock, and wherein the security protocol cancomprise inclusion of non-real time clock data associated with themeasurement data in the transmission. Transmission of measurement datawith the associated non-real time clock data can causes the remotecomputing device to utilize the non-real time clock data to correlatethe measurement data with real time clock data.

Although some of the disclosed embodiments illustrate arrangement ofelectronic components, such as sensors, in or on a wound dressing,disclosed component arrangements are not so limited. In someimplementations, the components can be arranged on another dressing,structure, or substrate or could be provided separately for beingpositioned over any wound, as broadly defined herein. Componentarrangements can be used for one or more of preventing or treating awound.

In some embodiments, one or more electronic components can be positionedon the side of a wound contact layer opposite the side that faces thewound. Systems and methods described herein are equally applicable tosuch arrangements of components. Any wound dressing embodiment describedherein can include features of any of the other described wound dressingembodiments. Similarly, any controller described herein can includefeatures of any of the other described wound dressing embodiments.Further, any device, component, or module described in a certainembodiment can include features of any of the other describedembodiments of the device, component, or module.

Any value of a threshold, limit, duration, etc. provided herein is notintended to be absolute and, thereby, can be approximate. In addition,any threshold, limit, duration, etc. provided herein can be fixed orvaried either automatically or by a user. Furthermore, as is used hereinrelative terminology such as exceeds, greater than, less than, etc. inrelation to a reference value is intended to also encompass being equalto the reference value. For example, exceeding a reference value that ispositive can encompass being equal to or greater than the referencevalue. In addition, as is used herein relative terminology such asexceeds, greater than, less than, etc. in relation to a reference valueis intended to also encompass an inverse of the disclosed relationship,such as below, less than, greater than, etc. in relations to thereference value. Moreover, although blocks of the various processes maybe described in terms of determining whether a value meets or does notmeet a particular threshold, the blocks can be similarly understood, forexample, in terms of a value (i) being below or above a threshold or(ii) satisfying or not satisfying a threshold.

Features, materials, characteristics, or groups described in conjunctionwith a particular aspect, embodiment, or example are to be understood tobe applicable to any other aspect, embodiment or example describedherein unless incompatible therewith. All of the features disclosed inthis specification (including any accompanying claims, abstract anddrawings), or all of the steps of any method or process so disclosed,may be combined in any combination, except combinations where at leastsome of such features or steps are mutually exclusive. The protection isnot restricted to the details of any foregoing embodiments. Theprotection extends to any novel one, or any novel combination, of thefeatures disclosed in this specification (including any accompanyingclaims, abstract and drawings), or to any novel one, or any novelcombination, of the steps of any method or process so disclosed.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of protection. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms. Furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made. Those skilled in the art willappreciate that in some embodiments, the actual steps taken in theprocesses illustrated or disclosed may differ from those shown in thefigures. Depending on the embodiment, certain of the steps describedabove may be removed, others may be added. For example, the actual stepsor order of steps taken in the disclosed processes may differ from thoseshown in the figure. Depending on the embodiment, certain of the stepsdescribed above may be removed, others may be added. For instance, thevarious components illustrated in the figures may be implemented assoftware or firmware on a processor, controller, ASIC, FPGA, ordedicated hardware. Hardware components, such as controllers,processors, ASICs, FPGAs, and the like, can include logic circuitry.Furthermore, the features and attributes of the specific embodimentsdisclosed above may be combined in different ways to form additionalembodiments, all of which fall within the scope of the presentdisclosure.

Although the present disclosure includes certain embodiments, examplesand applications, it will be understood by those skilled in the art thatthe present disclosure extends beyond the specifically disclosedembodiments to other alternative embodiments or uses and obviousmodifications and equivalents thereof, including embodiments which donot provide all of the features and advantages set forth herein.Accordingly, the scope of the present disclosure is not intended to belimited by the specific disclosures of preferred embodiments herein, andmay be defined by claims as presented herein or as presented in thefuture.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, or steps are in anyway required for one or more embodiments or that one or more embodimentsnecessarily include logic for deciding, with or without user input orprompting, whether these features, elements, or steps are included orare to be performed in any particular embodiment. The terms“comprising,” “including,” “having,” and the like are synonymous and areused inclusively, in an open-ended fashion, and do not excludeadditional elements, features, acts, operations, and so forth. Also, theterm “or” is used in its inclusive sense (and not in its exclusivesense) so that when used, for example, to connect a list of elements,the term “or” means one, some, or all of the elements in the list.Further, the term “each,” as used herein, in addition to having itsordinary meaning, can mean any subset of a set of elements to which theterm “each” is applied.

Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than 10% of, within less than 5% of, within less than 1% of, withinless than 0.1% of, and within less than 0.01% of the stated amount. Asanother example, in certain embodiments, the terms “generally parallel”and “substantially parallel” refer to a value, amount, or characteristicthat departs from exactly parallel by less than or equal to 15 degrees,10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

The scope of the present disclosure is not intended to be limited by thespecific disclosures of preferred embodiments in this section orelsewhere in this specification, and may be defined by claims aspresented in this section or elsewhere in this specification or aspresented in the future. The language of the claims is to be interpretedbroadly based on the language employed in the claims and not limited tothe examples described in the present specification or during theprosecution of the application, which examples are to be construed asnon-exclusive.

What is claimed is:
 1. A wound monitoring and/or therapy apparatuscomprising: a wound dressing configured to be positioned in contact witha wound of a patient, the wound dressing comprising one or more sensorsconfigured to obtain a measurement data of at least one of the wound ora periwound; and a controller configured to: maintain a device clockindicative of a non-real time clock by counting from a random number ora unique hardware identification number of the controller; receive themeasurement data obtained by the one or more sensors; and transmit themeasurement data to a remote computing device according to a securityprotocol, the security protocol comprising including the device clockassociated with the measurement data in the transmission and notincluding a patient identification information and a real time clock inthe transmission to prevent associating the measurement data with thepatient identification information in case the apparatus is hacked. 2.The apparatus of claim 1, wherein the wound dressing comprises asubstantially flexible wound contact layer supporting the one or moresensors.
 3. The apparatus of claim 1, wherein the security protocolfurther comprises encrypting the measurement data.
 4. The apparatus ofclaim 1, wherein transmission of the measurement data with theassociated device clock data causes the remote computing device toutilize the device clock data to correlate the measurement data with thereal time clock.
 5. The apparatus of claim 4, wherein: the controller isfurther configured to transmit initial device clock data to the remotecomputing device during initialization; and transmission of themeasurement data with the associated device clock data causes the remotecomputing device to determine elapsed time relative to the initialtransmission based on comparison of the initial device clock data anddevice clock data associated with the measurement data to obtain a realtime clock value associated with the measurement data.
 6. The apparatusof claim 1, wherein the controller is configured to maintain the deviceclock when power is supplied to the controller.
 7. The apparatus ofclaim 6, wherein, in response to a power interruption, the controller isfurther configured to reestablish the device clock from a previousdevice clock value before the power interruption.
 8. The apparatus ofclaim 1, wherein the patient identification information is not stored bythe wound dressing and controller, and wherein the measurement data isidentified by the unique hardware identification number of thecontroller.
 9. The apparatus of claim 1, wherein the controller isfurther configured to: transmit a first set of the measurement data tothe remote computing device according to the security protocol, thefirst set of the measurement data obtained by the one or more sensorsduring a first time duration; in response to transmission of the firstset of the measurement data to the remote computing device not beingsuccessful, instruct the wound dressing to stop logging the measurementdata; and in response to transmission of the first set of themeasurement data to the remote computing device being successful,transmit a second set of the measurement data to the remote computingdevice according to the security protocol, the second set of themeasurement data obtained by the one or more sensors during a secondtime duration subsequent to the first time duration.
 10. A woundmonitoring and/or therapy system comprising: a wound monitoring and/ortherapy apparatus comprising a wound dressing configured to bepositioned proximate a wound of a patient and a controller, thecontroller configured to: maintain a device clock indicative of anon-real time clock by counting from a random number or a uniquehardware identification number, receive a measurement data obtained byone or more sensors supported by the wound dressing, and transmit thedevice clock along with the measurement data to a remote computingdevice according to a security protocol that comprises including in thetransmission the device clock associated with the measurement data andnot including in the transmission a patient identification informationand a real time clock; a communication device configured to be connectedto the controller and further configured to periodically receive datafrom the controller; and a computing device configured to be connectedto the communication device, the computing device further configured toreceive data from the communication device, the computing device furtherconfigured to be connected to another remote computing device configuredto receive and aggregate data from the computing device.
 11. The systemof claim 10, further comprising another computing device configured toobtain one or more images of at least one of the wound or a periwound.12. The system of claim 11, wherein the computing device is configuredto communicate the one or more images to the another remote computingdevice.
 13. The system of claim 10, wherein the wound dressing furtherincludes an antenna configured to communicate the measurement data to atleast one of the controller or communication device.
 14. The system ofclaim 10, further comprising a skin perfusion measurement deviceconfigured to measure skin perfusion pressure in a target area of thepatient, wherein the computing device is further configured to beconnected to the perfusion measurement device and receive data from theperfusion measurement device.
 15. The system of claim 10, wherein thecommunication device is configured to be connected to the controllerusing near field communication (NFC) protocol.
 16. A method of operatinga wound dressing configured to be positioned in contact with a wound ofa patient, the wound dressing including one or more sensors configuredto obtain measurement data of at least one of the wound or a periwound,the method comprising: by a controller configured to be connected to orsupported by the wound dressing: maintaining a device clock indicativeof a non-real time clock by counting from a random number or a uniquehardware identification number; receiving a measurement data obtained bythe one or more sensors; and transmitting the measurement data to aremote computing device according to a security protocol by includingthe device clock associated with the measurement data in thetransmission and not including a patient identification information anda real time clock in the transmission.
 17. The method of claim 16,wherein transmission of the measurement data with the associated deviceclock data causes the remote computing device to utilize the deviceclock data to correlate the measurement data with real time clock data.18. The method of claim 17, further comprising, by the controller,transmitting initial device clock data to the remote computing deviceduring initialization, wherein transmission of the measurement data withthe associated device clock data causes the remote computing device todetermine elapsed time relative to the initial transmission based oncomparison of the initial device clock data and device clock dataassociated with the measurement data.
 19. The method of claim 16,further comprising maintaining the device clock when power is suppliedto the controller.
 20. The method of claim 16, further comprising, inresponse to a power interruption, reestablishing the device clock from aprevious device clock value before the power interruption.